Nutrition
LEARNING OBJECTIVES
After completing the study of this concept, you will be able to:
▶ Apply basic guidelines for healthy eating.
Concept 14
▶ List and apply dietary recommendations for carbohydrates, fats, proteins, vitamins,
minerals, and water.
▶ Interpret and use food labels to make healthy decisions.
▶ Describe and incorporate sound eating practices.W
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▶ Describe and apply nutrition
guidelines for active people
and those interested in
performance (e.g., sports).
▶ Analyze your diet to
determine nutrient quality.
▶ Compare nutritional quality
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of various foods.
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The amount and kinds of food
you eat affect your health
and wellness.
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Section 5 ▶ Nutrition and Body Composition
he importance of good nutrition for optimal health is
well established. Eating patterns have been related to
four of the seven leading causes of death, and poor nutrition increases the risks for numerous diseases, including heart disease, obesity, stroke, diabetes, hypertension,
osteoporosis, and many cancers (e.g., colon, prostate,
mouth, throat, lung, and stomach). The American Cancer
Society estimates that 35 percent of cancer risks are related
to nutritional factors. In addition to helping avoid these
health risks, proper nutrition can enhance the quality of
life by improving appearance and increasing the ability to
carry out work and leisure-time activity without fatigue.
Most people believe that nutrition is important but
still find it difficult to maintain a healthy diet. One reason for this is that foods are usually developed, marketed,
and advertised for convenience and taste rather than for
health or nutritional quality. Another reason is that many
individuals have misconceptions about what constitutes
a healthy diet. Some of these misconceptions are propagated by commercial interests and so-called experts with
less than impressive credentials. Other misconceptions
are created by the confusing, and often contradictory,
news reports about new nutrition research. In spite of the
fact that nutrition is an advanced science, many questions
remain unanswered. This concept reviews important
national guidelines and recommendations for healthy
eating. The significance of essential dietary nutrients
is also described along with strategies for adopting and
maintaining a healthy diet.
guidelines be updated every 5 years to incorporate new
research findings. The most recent USDA nutrition
guidelines were published in 2010. Many other countries
release similar sets of guidelines specific to their population (e.g., Health Canada’s Food Guide).
Guidelines for Healthy Eating
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National
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National dietary guidelines provide a sound plan
for good nutrition. The U.S. Department of Agriculture
(USDA) and the Department of Health and Human Services (DHHS) publishes a definitive report called the
Dietary Guidelines for Americans to help consumers make
healthier food choices. Federal law requires that these
KEY PRINCIPLES
• Build a healthy plate.
• Cut back on foods high in solid
fats.
• Cut back on foods high in sugars
and salt.
• Eat the right amount of calories
for you.
• Be physically active your way.
The MyPlate model conveys a variety of key nutrition
principles. The U.S. Dietary Guidelines are developed
largely to help promote education about healthy eating.
Many of the key elements of the guidelines are summarized in the MyPlate model (see Figure 1) which replaces
the previous MyPyramid model as the primary symbol
or icon of the program. The four colored areas represent the different food groups (fruits, grains, vegetables,
and
Wproteins) and a glass represents the dairy food group
(including solid dairy products). The pyramid included
R same categories, but the plate helps a person visualthe
ize
I the recommended allocations in a typical meal. Fruits
and vegetables are emphasized in the MyPlate model
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(representing half of the plate) because they are high
inHnutrients and fiber and low in calories. The MyPlate
model also emphasizes healthy food choices in each
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category. For example, they recommend low-fat dairy
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choices
(e.g., shifting to skim milk) and making half of
your grains “whole” (i.e., whole grains). Key principles
highlighted in the MyPlate model are summarized to the
S of Figure 1. Like the pyramid, the MyPlate image is
left
widely
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number of other resources available to help consumers
apply
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dietary guidelines provide suggestions
for healthy eating. The current version of the national
Dietary Guidelines for Americans emphasizes a “total diet”
approach,
which is defined as the “combination of foods
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and beverages that provide energy and nutrients, and con7
stitute an individual’s complete dietary intake, on average,
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WHAT MAKES A HEALTHY PLATE?
• Make half your plate fruits and
vegetables.
• Switch to skim or 1% milk.
• Make at least half of your grains
whole.
• Vary your protein food choices.
• Keep your food safe to eat.
Figure 1 ▶ MyPlate presents a combination of nutrition guidelines and healthy food choices.
Source: Adapted from the USDA 2010, www.choosemyplate.gov
Concept 14 ▶ Nutrition
over time.” The information at the right of Figure 1
tells how to “build a plate” to meet the “total diet” goal.
The report further describes other key components of a
nutrient-dense total diet:
• Eat the right amount of calories for you. Effective weight
control requires balancing energy intake with energy
expenditure. The new guidelines encourage Americans
to achieve their recommended nutrient intakes by consuming foods within a total diet that meets, but does
not exceed, energy needs. This should be done using
personal information such as age, gender, current body
weight, and current physical activity levels. Studies
indicate that Americans underestimate the number of
calories they eat and only about 9 percent regularly
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keep track of the calories in the foods they eat.
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• Consume nutrient-dense foods. Americans consume less
than 20 percent of the recommended intakes for whole
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grains, less than 60 percent for vegetables, less than 50
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percent for fruits, and less than 60 percent for milk
and milk products. Consuming nutrient-dense foods
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improves the overall quality of the diet. Examples of
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nutrient-dense foods include vegetables, fruits, highfiber whole grains, fat-free or lowfat milk and milk
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products, seafood, lean meat and poultry, eggs, soy
products, nuts, seeds, and oils.
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• Reduce solid fats and added sugars (SoFAS). Evidence
indicates that solid fats and added sugars (SoFAS) conH
tribute about 35 percent of total calories, leading to
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excessive intake of saturated fat and cholesterol and
insufficient intake of dietary fiber and other nutrients.
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The guidelines recommend reducing consumption of
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SoFAS as an important diet strategy.
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• Reduce sodium intake. Excessive sodium in the diet can
increase blood pressure and lead to health problems.
• Be physically active your way. The USDA nutrition guide2
lines also emphasize the importance of daily physical
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activity (60 minutes each day) in energy balance. Most
Americans overestimate the number of calories that
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they expend in activity.
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Specific Dietary Reference Intakes (DRI) provide B
a
target zone for healthy eating. About 45 to 50 nutriU
ents in food are believed to be essential for the body’s
growth, maintenance, and repair. These are classified into
six categories: carbohydrates (and fiber), fats, proteins,
vitamins, minerals, and water. The first three provide
energy, which is measured in calories. Specific dietary
recommendations for each of the six nutrients are presented later in this concept.
In the United States, guidelines specifying the nutrient requirements for good health are developed by the
Food and Nutrition Board of the National Academy of
Science’s Institute of Medicine. Recommended Dietary
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Allowance (RDA) historically was used to set recommendations for nutrients, but the complexity of dietary
interactions prompted the board to develop a more
comprehensive and functional set of dietary intake recommendations. These broader guidelines, referred to as
Dietary Reference Intake (DRI), include RDA values
when adequate scientific information is available and estimated Adequate Intake (AI) values when sufficient data
aren’t available to establish a firm RDA. The DRI values
also include Tolerable Upper Intake Level (UL), which
reflects the highest level of daily intake a person can
consume without adverse effects on health (see Table 1).
The guidelines make it clear that although too little of a
nutrient can be harmful to health, so can too much. The
distinctions are similar to the concept of the target zone
used to prescribe exercise levels. The Recommended
Dietary Allowance (RDA) or Adequate Intake (AI) values
are analogous to the threshold levels (minimal amount
needed to meet guidelines), while the Upper Limit values
represent amounts that should not be exceeded.
A unique aspect of the DRI values is that they are categorized by function and classification in order to facilitate awareness of the different roles that nutrients play
in the diet. Specific guidelines have been developed for
B-complex vitamins; vitamins C and E; bone-building
nutrients, such as calcium and vitamin D; micronutrients,
such as iron and zinc; and the class of macronutrients that
includes carbohydrates, fats, proteins, and fiber. Table 1
includes the DRI values (including the UL values) for
most of these nutrients.
Nutrition recommendations are flexible, but also
highly individualized. A unique aspect of the nutrition
guidelines is that they highlight a variety of dietary patterns. The established DASH-style and Mediterraneanstyle dietary patterns were cited as examples of healthy
diets because they have been well-supported in the scientific literature. The guidelines also referenced traditional Asian dietary patterns and vegetarian diets as
Recommended Dietary Allowance (RDA) Dietary
guideline that specifies the amount of a nutrient
needed for almost all of the healthy individuals in a
specific age and gender group.
Dietary Reference Intake (DRI) Appropriate
amounts of nutrients in the diet (AI, RDA, and UL).
Adequate Intake (AI) Dietary guideline established
experimentally to estimate nutrient needs when sufficient data are not available to establish an RDA value.
Tolerable Upper Intake Level (UL) Maximum
level of a daily nutrient that will not pose a risk of
adverse health effects for most people.
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Section 5 ▶ Nutrition and Body Composition
Table 1 ▶ Dietary Reference Intake (DRI), Recommended Dietary Allowance (RDA),
and Tolerable Upper Intake Level (UL) for Major Nutrients
DRI/RDA
Males
Females
UL
Function
Carbohydrates (45–65%)
130 g
130 g
ND
Energy (only source of energy for the brain)
Fat (20–35%)
ND
ND
ND
Energy, vitamin carrier
Protein (10–35%)
.8 g/kg
.8 g/kg
ND
Growth and maturation, tissue formation
Fiber (g/day)
38 g/day*
25 g/day*
ND
Digestion, blood profiles
Energy and Macronutrients
B-Complex Vitamins
Thiamin (mg/day)
1.2
1.1
ND
Riboflavin (mg/day)
1.3
1.1
ND
Niacin (mg/day)
16
14
35
Vitamin B-6 (mg/day)
1.3
1.3
100
Folate (μg/day)
400
400
1,000
Vitamin B-12 (μg/day)
2.4
2.4
ND
Pantothenic acid (mg/day)
5*
5*
ND
Biotin (μg/day)
30*
30*
ND
Choline (mg/day)
550*
425*
3,500
Vitamin C (mg/day)
90
75
2,000
Vitamin E (mg/day)
15
15
1,000
Selenium (μg/day)
55
55
400
Antioxidants and Related
Nutrients
Bone-Building Nutrients
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Co-enzyme for carbohydrates and amino acid metabolism
Co-enzyme for metabolic reactions
Co-enzyme for metabolic reactions
Co-enzyme for amino acid and glycogen reactions
Metabolism of amino acids
Co-enzyme for nucleic acid metabolism
Co-enzyme for fat metabolism
Synthesis of fat, glycogen, and amino acids
Precursor to acetylcholine
Co-factor for reactions, antioxidant
Undetermined, mainly antioxidant
Defense against oxidative stress
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Calcium (mg/day)
1,000*
1,000*
2,500
Muscle contraction, nerve transmission
Phosphorus (mg/day)
700
700
3,000
Magnesium (mg/day)
400–420
310–320
350
Vitamin D (μg/day)
5*
5*
50
Fluoride (mg/day)
4*
3*
10
Vitamin K (μg/day)
120*
90*
ND
Blood clotting and bone metabolism
Vitamin A (μg/day)
900
700
3,000
Vision, immune function
Iron (mg/day)
8
18
45
Component of hemoglobin
Zinc (mg/day)
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8
40
Component of enzymes and proteins
Maintenance of pH, storage of energy
Co-factor for enzyme reactions
Maintenance of calcium and phosphorus levels
Stimulation of new bone formation
Micronutrients and Other
Trace Elements
Note: These values reflect the dietary needs generally for adults aged 19–50 years. Specific guidelines for other age groups are available from the Food and
Nutrition Board of the National Academy of Sciences (www.iom.edu). Values labeled with an asterisk (*) are based on Adequate Intake (AI) values rather than
the RDA values; ND = not determined.
Concept 14 ▶ Nutrition
examples of ways to achieve dietary goals. The new guidelines emphasize that a healthful total diet is not a rigid
prescription but rather a flexible approach to eating that
can be adjusted for a variety of individual tastes and preferences. The flexibility for individual eating patterns is
also reflected in the wide ranges provided for various DRI
categories. The recommended DRI values for carbohydrates range from 45 to 65 percent. The DRI values for
protein range from 10 to 35 percent, while the DRI values for fat range from 20 to 35 percent. These ranges are
much broader than recommendations from the USDA
in previous versions of the dietary guidelines. According
to the Institute of Medicine (IOM), this broader range
was established to “help people make healthy and more
realistic choices based on their own food preferences.”
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Figure 2 illustrates the recommended DRI distributions
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for carbohydrates, fats, and proteins.
The quantity of nutrients recommended varies with
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age and other considerations; for example, young children
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need more calcium than adults and pregnant women, and
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postmenopausal women need more calcium than other
women. Accordingly, DRIs, including RDAs, have been
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established for several age/gender groups. In this book,
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the values are appropriate for most
adult men and women. The USDA
has a website that calculates personVIDEO 1 S
ally determined DRI values. You
can enter data such as your gender,
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age, height, weight, and activity level, and the calculator
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determines your DRI values. (Search “USDA DRI calculator” on the Internet.)
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Dietary Recommendations
for Carbohydrates
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Complex carbohydrates should be the principal
source of calories in the diet. Carbohydrates have
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gotten a bad rap in recent years due to the hype associated
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Protein
10–35%
Fat 20–35%
No more than 10%
saturated fat
Carbohydrate
45–65%
Figure 2 ▶ Dietary Reference Intake values.
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with low-carbohydrate diets. Carbohydrates have been
unfairly implicated as a cause of obesity. The suggestion
that they cause insulin to be released and that insulin, in
turn, causes the body to take up and store excess energy
as fat is overly simplistic and doesn’t take into account
differences in types of carbohydrates. Simple sugars (such
as sucrose, glucose, and fructose) found in candy and soda
lead to quick increases in blood sugar and tend to promote fat deposition. Complex carbohydrates (e.g., bread,
pasta, rice), on the other hand, are broken down more
slowly and do not cause the same effect on blood sugar.
They contribute valuable nutrients and fiber in the diet
and should constitute the bulk of a person’s diet. Lumping simple and complex carbohydrates together is not
appropriate, since they are processed differently and have
different nutrient values.
A number of low-carb diet books have used an index
known as the glycemic index (GI) as the basis for determining if foods are appropriate in the diet. Foods with
a high GI value produce rapid increases in blood sugar,
while foods with a low GI value produce slower increases.
While this seems to be a logical way to categorize carbohydrates, it is misleading, since it doesn’t account for the
amount of carbohydrates in different servings of a food.
A more appropriate indicator of the effect of foods on
blood sugar levels is called the glycemic load. Carrots,
for example, are known to have a very high GI value, but
the overall glycemic load is quite low. The carbohydrates
from most fruits and vegetables exhibit similar properties.
Despite the intuitive and logical appeal of this classification system, neither the glycemic index nor glycemic load
have been consistently associated with body weight. Evidence also indicates no difference on weight loss between
high glycemic index and low glycemic index diets. There
is some evidence linking glycemic load to a higher risk for
diabetes but no associations with cancer risk.
Additional research is needed, but excess sugar consumption appears to be problematic only if caloric
intake is larger than caloric expenditure. Carbohydrates
are the body’s preferred form of energy for physical
activity, and the body is well equipped for processing
extra carbohydrates. Athletes and other active individuals typically have no difficulty burning off extra energy
from carbohydrates. Sugar consumption, among people
with an adequate diet, is also not associated with major
chronic diseases.
Reducing dietary sugar can help reduce risk of
obesity and heart disease. Although sugar consumption has not been viewed as harmful, people who consume high amounts of sugar also tend to consume excess
calories. The new dietary guidelines clearly recommend
decreasing consumption of added sugars to reduce risk of
excess calorie consumption and weight gain. The American Heart Association also endorsed this position in a
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Section 5 ▶ Nutrition and Body Composition
scientific statement entitled “Dietary Sugars Intake and
Cardiovascular Health.”
The document notes that excessive consumption of
sugars (sugars added to foods and drinks) contributes
to overconsumption of discretionary calories. Among
Americans, the current average daily sugars consumption
is 355 calories per day (22.2 teaspoons) as opposed to 279
calories in 1970. Soft drinks and sugar-sweetened beverages are the primary sources of added sugars in the American diet. The AHA’s scientific statement recommends no
more than 100 calories of added sugars for most women
and not more than 150 calories for most men. A typical 12-ounce sweetened soft drink contains 150 calories,
mostly sugar. Reducing consumption of sugar-sweetened
beverages is a simple, but important, diet modification.
Increasing consumption of dietary fiber is important
for overall good nutrition and health. Diets high in
complex carbohydrates and fiber are associated with a
low incidence of coronary heart disease, stroke, and some
forms of cancer. Long-term studies indicate that highfiber diets may also be associated with a lower risk for
diabetes mellitus, diverticulosis, hypertension, and gallstone formation. It is not known whether these health
benefits are directly attributable to high dietary fiber or
other effects associated with the ingestion of vegetables,
fruits, and cereals.
A position statement from the American Dietetics
Association summarizes the health benefits and importance of fiber in a healthy diet. It indicates that high-fiber
diets provide bulk, are more satiating, and are linked to
lower body weights. It also points out that a fiber-rich
diet often has a lower fat content, is larger in volume, and
is richer in micronutrients, all of which have beneficial
health effects. Evidence for health benefits has become
strong enough that the FDA has stated that specific beneficial health claims can be made for specific dietary fibers.
The National Cholesterol Education Program also recommends dietary fiber as part of overall strategies for
treating high cholesterol in adults.
In the past, clear distinctions were made between soluble fiber and insoluble fiber because they appeared to
provide separate effects. Soluble fiber (typically found in
fruits and oat bran) was more frequently associated with
improving blood lipid profiles, while insoluble fiber (typically found in grains) was mainly thought to help speed up
digestion and reduce risks for colon and rectal cancer. Difficulties in measuring these compounds in typical mixed
diets led a National Academy of Sciences panel to recommend eliminating distinctions between soluble and insoluble fibers and instead to use a broader definition of fiber.
Currently, few Americans consume the recommended
amounts of dietary fiber. The average intake of dietary
fiber is about 15 g/day, which is much lower than the recommended 25 to 35 g/day. Foods in the typical American
diet contain little, if any, dietary fiber, and servings of
commonly consumed grains, fruits, and vegetables contain only 1 to 3 g of dietary fiber. Therefore, individuals
have to look for ways to ensure that they get sufficient
fiber in their diet. Manufacturers are allowed to declare
a food as a “good source of fiber” if it contains 10 percent of the recommended amount (2.5 g/serving) and
an “excellent source of fiber” if it contains 20 percent of
the recommended amount (5 g/serving). Because fiber
has known health benefits, the new dietary guidelines
encourage consumers to select foods high in dietary fiber,
such as whole-grain breads and cereals, legumes, vegetables, and fruit, whenever possible.
Fruits
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Fruits and vegetables are a valuable source of dietary
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tain
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beneficial effects on health. The International Agency
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of Research on Cancer (IARC), an affiliate of the World
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Health
links between dietary intake of fruits and vegetables and
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cancer. It concluded that both human studies and animal
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experimental
studies “indicate that a higher intake of
fruits and vegetables is associated with a lower risk of various types of cancer.” The clearest evidence of a cancerS
protective
effect from eating more fruits is for stomach,
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Plan ahead for healthy, low-fat snacks when on the run.
Concept 14 ▶ Nutrition
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lung, and esophageal cancers. A higher intake of vegetables is also associated with reduced risks for cancers of the
esophagus and colon-rectum. This evidence—plus the
evidence of the beneficial effects of fruits and vegetables
on other major diseases, such as heart disease—indicates
that individuals should strive to increase their intake of
these foods. Reports from the 2010 Dietary Guidelines
Advisory Committee indicate that beneficial effects on
health appear to be linked to a minimum of five servings
of fruits and vegetables per day. Additional benefits were
noted at even higher consumption levels. These findings
contributed to the increased emphasis being placed on a
plant-based diet in the new dietary guidelines.
Follow the recommendations to assure healthy
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amounts of carbohydrates in the diet. The following
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list summarizes key strategies to achieve dietary guidelines for carbohydrate content in the diet:
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• Consume a variety of fiber-rich fruits and vegetables.G
• Select whole-grain foods when possible.
• Choose and prepare foods and
beverages with little added sugars
or caloric sweeteners.
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Fat is an essential nutrient and an important energy
source. Humans need some fat in their diet because fats
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are carriers of vitamins A, D, E, and K. They are a source
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of essential linoleic acid, they make food taste better, and
they provide a concentrated form of calories, which serve
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Dietary Recommendations
for Fat
as a vital source of energy during moderate to vigorous
exercise. Fats have more than twice the calories per gram
as carbohydrates.
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There are several types of dietary fat. Saturated fats
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come primarily from animal sources, such as red meat,
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dairy products, and eggs, but they are also found in some
vegetable sources, such as coconut and palm oils. There
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are two basic types of unsaturated fats: polyunsaturated
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and monounsaturated. Polyunsaturated fats are derived
principally from vegetable sources, such as safflower, cotU
tonseed, soybean, sunflower, and corn oils (omega-6 fats),
and cold-water fish sources, such as salmon and mackerel (omega-3 fats). Monounsaturated fats are derived
primarily from vegetable sources, including olive, peanut,
and canola oil.
Saturated fat is associated with an increased risk
for disease, but polyunsaturated and monounsaturated fats can be beneficial. Excessive total fat in the
diet (particularly saturated fat) is associated with atherosclerotic cardiovascular diseases and breast, prostate, and
Being an informed and educated consumer can help you make
healthier food choices.
colon cancer, as well as obesity. Excess saturated fat in the
diet contributes to increased cholesterol and increased
low-density lipoprotein (LDL) cholesterol in the blood.
For this reason, no more than 10 percent of your total
calories should come from saturated fats.
Unsaturated fats are generally considered to be less
likely to contribute to cardiovascular disease, cancer,
and obesity than saturated fats. Polyunsaturated fats can
Fiber Indigestible bulk in foods that can be either
soluble or insoluble in body fluids.
Saturated Fats Dietary fats that are usually solid at
room temperature and come primarily from animal
sources.
Unsaturated Fats Monounsaturated or polyunsaturated fats that are usually liquid at room temperature and come primarily from vegetable sources.
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Section 5 ▶ Nutrition and Body Composition
reduce total cholesterol and LDL cholesterol, but they
also decrease levels of high-density lipoprotein (HDL)
cholesterol. Omega-3 fatty acids (a special type of polyunsaturated fat found in cold-water fish) have received a
lot of attention due to their potential benefits in reducing the risk of cardiovascular disease. A plant source of
omega-3 fatty acids (alpha-linolenic acid) found in walnuts, flaxseed, and canola oil may have similar benefits.
Monounsaturated fats have been shown to decrease
total cholesterol and LDL cholesterol without an accompanying decrease in the desirable HDL cholesterol. Past
dietary guidelines recommended a diet low in saturated
fat and cholesterol but moderate in total fat, making it
clear that excess saturated fat is the main concern and
that some fat is necessary in the diet. Fat should account
for 20 to 35 percent of calories in the diet, with no more
than 10 percent of total calories from saturated fat. The
remaining fat should come from plant-based sources,
especially monounsaturated fats.
Trans fats and hydrogenated vegetable oils should
be minimized in the diet. For decades, the public has
been cautioned to avoid saturated fats and foods with
excessive cholesterol. Many people switched from using
butter to margarine because margarine is made from vegetable oils that are unsaturated and contain no cholesterol. The hydrogenation process used to convert oils into
solids, however, is known to produce trans fats, which
are just as harmful as saturated fats, if not more so. Trans
fats are known to cause increases in LDL cholesterol and
have been shown to contribute to the buildup of atherosclerotic plaque. Because of these effects, it is important
to try to minimize consumption of trans fats in your diet.
The FDA requires trans fat content to be listed on
the nutrition facts labels so that consumers can be more
aware of foods high in this fat. The requirement to post
trans fat content on food labels has prompted companies
to look for ways to remove excess trans fats from products. Lay’s uses cottonseed oil instead of sunflower oil to
help eliminate trans fats from Fritos, Tostitos, and Cheetos. A number of margarines are also available with little
or no trans fat (e.g., Smart Balance). These changes and
the increased awareness about trans fat appear to have
had a positive effect. The CDC reports that levels of trans
fat have declined in the population by over 58 percent.
These findings provide an effective example of how food
policy (e.g., labeling) has prompted positive changes in
food quality and food access. The Dietary Guidelines
continue to recommend that consumers keep trans fat
consumption as low as possible by limiting solid fats and
foods that contain synthetic sources of trans fats. Foods
that have trace amounts of trans fat (i.e., those containing
less than .5 g of trans fat per serving) may still be listed as
having no trans fat. Therefore, you should also look for
foods that contain little or no hydrogenated vegetable oil.
Fat substitutes and neutraceuticals in food
products may reduce fat consumption and lower
cholesterol. Olestra is a synthetic fat substitute that
passes through the gastrointestinal system without being
digested. Thus, foods prepared with Olestra have fewer
calories. For example, a chocolate chip cookie prepared
in a normal way would have 138 calories, but an Olestra
cookie would have 63. Some consumer groups warn that
the promotion of Olestra-containing products may make
individuals more likely to snack on less energy-dense
snack foods. They also express concern that Olestra
inhibits absorption of many naturally occurring antioxidants that have been shown to have many beneficial
effects on health. Early warnings were required on the
product
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These warnings were removed by the FDA soon after
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Olestra
I Several other new products offer potential to modify
the amount and effect of dietary fat in our diets. The
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first is a naturally occurring compound included in several
H margarines (Benecol and Take Control). The active
ingredient in this compound (sitostanol ester) comes
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from pine trees and has been shown to reduce total
, LDL cholesterol in the blood. Several clinical triand
als have confirmed that these margarines are both safe
and effective in lowering cholesterol levels. The products
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must
only
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Food products that contain these medically beneficial
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compounds
are often referred to as neutraceuticals, or
functional
foods,
because they are a combination of pharR
maceuticals and food.
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Follow
the recommendations to assure healthy
amounts of fat in the diet. The 2010 Dietary Guidelines Advisory Committee emphasized that significant
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health benefits can be achieved by making several changes
in7consumption of dietary fats and cholesterol.
• 9Limit saturated fatty acid intake to less than 10 percent
total calories, with continued gradual reductions
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down to 7 percent. Substitute food sources of monoBor polyunsaturated fatty acids.
• ULimit dietary cholesterol to less than 300 mg per day
(200 mg per day for persons with or at high risk for
cardiovascular disease or Type II diabetes).
• Avoid trans fatty acids from processed foods (except
the small amounts that occur naturally from ruminant
sources in animals).
• Limit cholesterol-raising fats (saturated fats exclusive
of stearic acid and trans fatty acids) to less than 5 to 7
percent of energy.
• Consume two servings of seafood per week to provide healthy
VIDEO 3
Concept 14 ▶ Nutrition
amounts of omega-3 fatty acids from marine sources
(e.g., docosahexaenoic acid [DHA] and eicosapentaenoic acid [EPA]).
Dietary Recommendations
for Proteins
Protein is the basic building block for the body,
but dietary protein constitutes a relatively small
amount of daily caloric intake. Proteins are often
referred to as the building blocks of the body because all
body cells are made of protein. More than 100 proteins
are formed from 20 different amino acids. Eleven of
W
these amino acids can be synthesized from other nutrients, but 9 essential amino acids must be obtained
R
directly from the diet. One way to identify amino acids is
I
the -ine at the end of their name. For example, arginine
and lysine are two of the amino acids. Only 3 of the 20
G
amino acids do not have the -ine suffix. They are aspartic
H
acid, glutamic acid, and tryptophan.
T
Certain foods, called complete proteins, contain all of
the essential amino acids, along with most of the others.
,
Examples are meat, dairy products, and fish. Incomplete
proteins contain some, but not all, of the essential amino
acids. Examples include beans, nuts, and rice.
S
Protein should account for at least 10 percent of daily
H
calorie consumption, which can be met easily with complete (animal) or incomplete (vegetable) sources of proE
tein. A person consuming a typical 2,000-calorie diet
R
should consume approximately 200 calories from protein.
Protein provides 4 calories per gram, so minimum daily
R
protein needs are as low as 50 grams per day. Figure 3
Y
shows the relative protein content of various foods.
1 glass milk
=
8 grams
1 ounce chicken breast
=
7 grams
1 slice bread
=
3 grams
1
–2
cup vegetables
=
2 grams
1
–2
cup navy beans
=
7 grams
Figure 3 ▶ Protein content of various foods.
Source: Williams, M.
2
7
9
3
B
U
331
To provide more flexibility, dietary guidelines indicate
that protein can account for as much as 35 percent of
calorie intake. Experts, however, agree that there are no
known benefits and some possible risks associated with
consuming excess protein, particularly animal protein.
High-protein diets are damaging to the kidneys, as the
body must process a lot of extra nitrogen. Excessive protein intake can also lead to urinary calcium loss, which
can weaken bones and lead to osteoporosis.
People who eat a variety of foods, including meat,
dairy, eggs, and plants rich in protein, virtually always
consume more protein than the body needs. Because of
the negative consequences associated with excess intake,
dietary supplements containing extra protein are not recommended for the general population.
Vegetarian diets provide sufficient protein and may
offer health benefits. Vegetarian diets provide ample
sources of protein as long as a variety of protein-rich
food sources are included in the diet. According to the
American Dietetics Association, well-planned vegetarian diets “are appropriate for all stages of the life cycle,
including during pregnancy, and lactation,” and can “satisfy the nutrient needs of infants, children, and adolescents.” You can get enough protein as long as the variety
and amounts of foods consumed are adequate. Vegans
must supplement the diet with vitamin B-12 because the
only source of this vitamin is food from animal sources.
Lacto-ovo vegetarians do not have the same concerns
because vitamin B-12 can be obtained in dairy products.
There is an increased recognition of the importance of
whole grains, fruits, and vegetables in the diet, but vegetarian diets based primarily on plants are still uncommon.
A Harris poll estimates that approximately 3 percent of
Americans are vegetarian (.5 percent vegan). However,
an additional 10 percent of the population indicates they
Trans Fats Fats that result when hydrogen is added
to liquid oil to make it more solid. Hydrogenation
transforms unsaturated fats so that they take on the
characteristics of saturated fats, as is the case for margarine and shortening.
Amino Acids The 20 basic building blocks of the
body that make up proteins.
Essential Amino Acids The nine basic amino acids
that the human body cannot produce and that must
be obtained from food sources.
Vegans Strict vegetarians, who exclude not only all
forms of meat from the diet but also dairy products
and eggs.
Lacto-Ovo Vegetarians Vegetarians who include
dairy and eggs in the diet.
332
Section 5 ▶ Nutrition and Body Composition
follow a vegetarian-inclined diet. Research has widely
supported the health benefits associated with vegetarian
diets and trends suggest that it is growing in popularity.
An increasing array of soy foods are available to
provide alternative sources of protein. Soybeans
and soy-based foods are a high-quality source of protein.
They may also have beneficial effects on blood pressure
and cholesterol levels, possibly contributing to reductions in risk for coronary heart disease. Soy-based foods
contain compounds called isoflavones, a phytoestrogen
that contributes to bone health, immune function, and
maintenance of menopausal health in women. A variety
of soy-based food products are commercially available as
alternatives to traditional meat foods. Common options
include tofu, tempeh, soy milk, or textured vegetable
(soy) protein. Grocery stores carry a variety of other
meatless products based on soy (e.g., veggie burgers). Soy
foods that contain at least 6.25 grams per serving can be
labeled with FDA-approved health claims.
Follow the recommendations to assure healthy
amounts of protein in the diet. The following list summarizes some key dietary recommendations for protein:
• Of the three major nutrients that provide energy,
protein should account for the smallest percentage of
total calories consumed (10 to 35 percent).
• Protein in the diet should meet the RDA of 0.8 gram
per kilogram (2.2 pounds) of a person’s weight (about
54 grams for a 150-pound person).
• People on low-calorie diets need to consume a higher
percentage of protein in the diet. In contrast, people
consuming a lot of calories need a lower percentage.
• Vegetarians must eat a combination of foods to assure
an adequate intake of essential amino acids. Vegans
should supplement their diet with vitamin B-12.
• Excess protein can be harmful to the kidneys. Protein
in the diet should not exceed twice the RDA (1.6 grams
per kilogram of body weight).
• Dietary supplements of protein, such as tablets and
powders, are not recommended.
B-complex vitamins and vitamin C) are water soluble
and are excreted in urine. These vitamins must be consumed on a daily basis. Other vitamins, such as A, D, E,
and K, are fat soluble. These vitamins are stored over
time, so daily doses of these vitamins are not necessary.
Excess consumption of fat-soluble vitamins can actually
build to toxic levels and harm cell function and health.
The specific DRI values (minimal amounts) for some
of the more important vitamins are shown in Table 1,
along with the Tolerable Upper Intake Levels (maximum
amounts).
Some vitamins act as antioxidants, but health
benefits may depend on other compounds in foods.
Carotenoid-rich
foods, such as carrots and sweet potatoes,
W
contain high amounts of vitamin A and high amounts of
R
beta-carotene.
Diets high in vitamin C (e.g., citrus fruits)
and
vitamin
E
(e.g.,
green leafy vegetables) are also assoI
ciated with reduced risk of cancer. Vitamin E has also
G
been associated with reduced risk of heart disease.
HVitamins A, C, and E (as well as beta-carotene) act as
antioxidants within the body. Antioxidants are substances
T
that are thought to inactivate free radicals (molecules
,
S
H
E
R
R
Y
2
7
9
3
B
U
Dietary Recommendations
for Vitamins
Adequate vitamin intake is necessary for good
health and wellness, but excessive vitamin intake
is not necessary and can be harmful. Vitamins serve
a variety of functions within the body. For example,
they serve as co-enzymes for metabolism of different
nutrients, contribute to the regulation of energy stores,
and assist in immune function. Some vitamins (e.g.,
Fruits and vegetables contain vitamins as well as health-promoting
phytochemicals.
Concept 14 ▶ Nutrition
that can cause cell damage and health problems). For
this reason, health benefits have been attributed to antioxidant properties. However, several large-scale studies
have shown no benefit (and possible risks) from taking
beta-carotene supplements. Another study of over 20,000
people failed to find health benefits associated with consumption of a daily mixture of vitamin E, vitamin C, and
beta-carotene. These results were difficult for scientists
to interpret, but it is now known that there may be other
beneficial substances in foods that contribute health
benefits.
As mentioned earlier, the designation of “functional
foods” has been coined to refer to foods or dietary components that may provide a health benefit beyond basic
nutrition. Fruits and vegetables, for example, are loaded
W
with a variety of powerful phytochemicals that have been
R
shown to have potential health benefits (see Table 2). The
relative importance to health of each compound is diffiI
cult to determine because the compounds may act synerG
gistically with each other (and with antioxidant vitamins)
H
to promote positive outcomes.
Other examples of functional foods include the benT
eficial types of fiber and beta glucan in whole grains,
,
the isoflavones in soy products, the omega-3 fatty acids
in cold-water fish, and the probiotic yeasts and bacteria in yogurts and other cultured dairy products. Most
S
vitamins and minerals are also classified as functional
foods, since they have functions beyond their primary
H
role in basic nutrition. The examples listed here and in
E
Table 2 should not be viewed as “magic bullets,” since
research is still accumulating on these compounds. In
R
general, diets containing a lot of fruits and vegetables
R
and whole grains (as recommended in MyPlate) will
provide adequate intake of vitamins and other healthy
Y
food components.
Table 2 ▶ Examples of Functional Foods and
Potential Benefits
Carotenoids
Potential Benefits
Beta-carotene: found in
carrots, pumpkin, sweet
potato, cantaloupe
May bolster cellular
antioxidant defenses
Lutein, zeaxanthin: found in
kale, collards, spinach, corn,
eggs, citrus
May contribute to healthy
vision
Lycopene: Found in
tomatoes, watermelon,
red/pink grapefruit
May contribute to prostate
health
Flavonoids
Anthocyanins: found in
berries, cherries, red grapes
Flavanones: found in citrus
foods
Potential Benefits
May bolster antioxidant
defenses; maintain brain
function and heart health
Flavonols: found in onions,
apples, tea, broccoli
Isothiocyanates
Potential Benefits
Proanthocyanidins: found in
cranberries, cocoa, apples,
strawberries, grapes, peanuts
May contribute to
maintenance of urinary tract
health and heart health
Sulforaphane: found in
cauliflower, broccoli,
brussels sprouts, cabbage,
kale, horseradish
May enhance detoxification
of undesirable compounds;
bolsters cellular antioxidant
defenses
Phenolic Acids
Caffeic/ferulic acids: found
in apples, pears, citrus fruits,
some vegetables, coffee
Sulfides/Thioles
Fortification of foods has been used to ensure
2
adequate vitamin intake in the population.
7
National policy requires many foods to be fortified. For
9
example, milk is fortified with vitamin D, low-fat milk
with vitamins A and D, and margarine with vitamin A.
3
These foods were selected because they are common
B
food sources for growing children. Many common grain
products are fortified with folic acid because low folic
U
acid levels increase the risk for birth defects in babies.
Fortification is considered essential, since more than
half of all women do not consume adequate amounts of
folic acid during the first months of gestation (before
most women even realize they are pregnant). Research
clearly demonstrates the value of fortification. One
study showed that neural tube defects are 19 percent less
likely today than in 1996 (prior to fortification). Though
other factors may have contributed to this decline, the
study supports the benefits of fortification for improving
nutritional intakes.
333
Sulfides: found in garlic,
onions, leeks, scallions
Dithiolthiones: found in
cruciferous vegetables
Potential Benefits
May bolster cellular antioxidant
defenses; may contribute to
maintenance of healthy vision
Potential Benefits
May enhance detoxification
of undesirable compounds;
may contribute to
maintenance of heart health
and healthy immune function
Taking a daily multiple vitamin supplement may be
a good idea. Sometimes supplements are needed to meet
specific nutrient requirements for specific groups. For
example, older people may need a vitamin D supplement if
they get little exposure to sunlight, and iron supplements
Antioxidants Vitamins that are thought to inactivate
“activated oxygen molecules,” sometimes called free
radicals. Free radicals may cause cell damage that leads
to diseases of various kinds. Antioxidants may inactivate the free radicals before they do their damage.
334
Section 5 ▶ Nutrition and Body Composition
are often recommended for pregnant women. Vitamin
supplements at or below the RDA are considered safe;
however, excess doses of vitamins can cause health problems. For example, excessively high amounts of vitamin C
are dangerous for the 10 percent of the population who
inherit a gene related to health problems. Excessively
high amounts of vitamin D are toxic, and mothers who
take too much vitamin A risk birth defects in unborn
children.
In the past some medical groups recommended a daily
multivitamin to insure adequate daily intake. However,
national dietary guidelines specifically note that “For
the general, healthy population, there is no evidence to
support a recommendation for the use of multivitamin/
mineral supplements in the primary prevention of chronic
disease.” In spite of this recommendation, some people
may choose to take a multivitamin/mineral supplement.
(Guidelines are presented in Table 3.)
Follow the recommendations to assure healthy
amounts of vitamins in the diet. Vitamins in the
amounts equal to the RDAs should be included in the diet
each day. The following guidelines will help you implement this recommendation:
• Eat a diet containing the recommended servings for
carbohydrates, proteins, and fats.
• Consume extra servings of green and yellow vegetables, citrus and other fruits, and other nonanimal food
sources high in fiber, vitamins, and minerals.
Table 3 ▶ Vitamin and Mineral Supplements
• Limit the use of supplements unless warranted because of a
health problem or a specific lack of nutrients in the diet.
• If you decide supplementation is necessary, select a
multivitamin/mineral supplement that contains micronutrients
in amounts close to the recommended levels (e.g., “one-aday”-type supplements).
• If your diet is deficient in a particular mineral (e.g., calcium or
iron), it may be necessary to incorporate dietary sources or an
additional mineral supplement as well, since most multivitamins
do not contain the recommended daily amount of minerals.
• Choose supplements that provide between 50 and 100
percent of the AI or RDA, and avoid those that provide
many times the recommended amount. The use of supplements that hype “megadoses” of vitamins and minerals can
increase the risk for some unwanted nutrient interactions and
possible toxic effects.
• Buy supplements from a reputable company and look for
supplements that carry the U.S. Pharmocopoeia (USP)
notation (www.usp.org).
Source: Manore.
• People with special needs should seek medical advice
before selecting supplements and should inform medical personnel as to the amounts and content of all supplements (vitamin and other).
Dietary Recommendations
for Minerals
Adequate mineral intake is necessary for good
health and wellness, but excessive mineral intake
is not necessary and can be harmful. Like vitamins,
minerals have no calories and provide no energy for the
body.
W They are important in regulating various bodily
functions. Two particularly important minerals are calR and iron. Calcium is important to bone, muscle,
cium
nerve,
I and blood development and function and has been
associated with reduced risk for heart disease. Iron is
G
necessary for the blood to carry adequate oxygen. Other
H
important
minerals are phosphorus, which builds teeth
and bones; sodium, which regulates water in the body;
T
zinc, which aids in the healing process; and potassium,
, is necessary for proper muscle function.
which
RDAs are established to determine the amounts of
each mineral necessary for healthy daily functioning. A
S diet provides all of the RDA for minerals. Evisound
dence
H indicating that some segments of the population
may be mineral-deficient has led to the establishment of
E goals identifying a need to increase mineral intake
health
for
Rsome people.
A National Institutes of Health (NIH) consensus
R
statement
indicates that a large percentage of Americans
fail
to
get
enough calcium in their diet and emphasizes
Y
the need for increased calcium—particularly for pregnant
women, postmenopausal women, and people over 65,
who
2 need 1,500 mg/day, which is higher than previous
RDA amounts. The NIH has indicated that a total intake
7
of 2,000 mg/day of calcium is safe and that adequate
9
vitamin
D in the diet is necessary for optimal calcium
absorption
to take place. Though getting these amounts
3
in a calcium-rich diet is best, calcium supplementation
Bthose not eating properly seems wise. Many multivifor
tamins
U do not contain enough calcium for some classes of
people, so some may want to consider additional calcium.
Check with your physician or a dietitian before you consider a supplement because individual needs vary.
Another concern is iron deficiency among very young
children and women of childbearing age. Low iron levels
may be a special problem for women taking birth control pills because the combination of low iron levels and
birth control pills has been associated with depression
and generalized fatigue. Eating the appropriate number
of servings recommended in MyPlate provides all the
minerals necessary for meeting the RDA for minerals.
Concept 14 ▶ Nutrition
Nutrition goals for the nation emphasize the importance
of adequate servings of foods rich in calcium, such as
green, leafy vegetables and milk products; adequate servings of foods rich in iron, such as beans, peas, spinach,
and meat; and reduced salt in the diet.
Follow the recommendations to assure healthy
amounts of minerals in the diet. The following list
includes basic recommendations for mineral content in
the diet:
• Minerals in amounts equal to the RDAs should be
consumed in the diet each day.
• In general, a calcium dietary supplement is not recommended for the general population; however, supW
plements (up to 1,000 mg/day) may be appropriate
R
for adults who do not eat well. For postmenopausal
women, a calcium supplement is recommended (up to
I
1,500 mg/day for those who do not eat well). A suppleG
ment may also be appropriate for people who restrict
calories, but RDA values should not be exceeded
H
unless the person consults with a registered dietitian
T
or a physician.
,
The following guidelines will help you implement these
recommendations:
• A diet containing the food servings recommended for
S
carbohydrates, proteins, and fats will more than meet
H
the RDA standards.
E
• Extra servings of green and yellow vegetables, citrus
and other fruits, and other nonanimal sources of foods
R
high in fiber, vitamins, and minerals are recommended
R
as a substitute for high-fat foods.
Y
Reducing salt in the diet can reduce health risks.
Salt is common in many processed food products and
most Americans consume way too much. Since the 1970s,
2
salt consumption has gone up 55 percent for men and
7
60 percent for women. Salt intake increases the risk for
9
hypertension, which is a major risk factor for heart disease and stroke. Many people have assumed that salt con3
sumption is not a problem if you are not hypertensive,
B
but this is not the case. Recent studies have shown that
sodium intake increases risks of stroke independent of
U
the presence of hypertension. Therefore, reducing salt
consumption is important for everyone.
Reducing salt consumption was emphasized as a key
priority in the latest Dietary Guidelines. The amount
of salt recommended in the diet was reduced from 2.5
grams, slightly less than one teaspoon per day, to 1.5
grams (about half a teaspoon) for both adults and children. This is because of the strong link between salt
intake and high blood pressure. The guidelines note it
will take time for most people to reduce salt intake, so it
may be done gradually. Increased potassium in the diet
335
is recommended because it helps reduce the effects of
sodium on blood pressure.
A prominent report by the Institute of Medicine and
the National Academy of Sciences indicates that reducing salt intake could prevent 100,000 deaths and save
$18 billion in medical expenses. A principal recommendation in the report is to encourage manufacturers to
reduce salt content in processed foods. Sodium content
is also high in fast foods. A study of 17 fast-food chains
showed that 85 percent of meals served had more than a
full day’s allotment of salt. While changes in food supply
are important, taking responsibility for lowering salt in
the diet is the best way for an individual to make change.
Dietary Recommendations
for Water and Other Fluids
Water is a critical component of a healthy diet.
Though water is not in the MyPlate food groups because
it contains no calories, provides no energy, and provides
no key nutrients, it is crucial to health and survival. Water
is a major component of most of the foods you eat, and
more than half of all body tissues are composed of it.
Regular water intake maintains water balance and is critical to many bodily functions. Though a variety of fluidreplacement beverages are available for use during and
following exercise, replacing water is the primary need.
Beverages other than water are a part of many
diets, but some beverages can have an adverse
effect on good health. Coffee, tea, soft drinks, and
alcoholic beverages are often substituted for water. Too
much caffeine consumption has been shown to cause
symptoms such as irregular heartbeat in some people. Tea
has not been shown to have similar effects, though this
may be because tea drinkers typically consume less volume than coffee drinkers, and tea has less caffeine per cup
than coffee. Many soft drinks also have caffeine, though
drip coffee typically contains two to three times the caffeine of a typical cola drink.
Excessive consumption of alcoholic beverages can have
negative health implications because the alcohol often
replaces nutrients. Excessive alcohol consumption is associated with increased risk for heart disease, high blood
pressure, stroke, and osteoporosis. Long-term excessive
alcoholic beverage consumption leads to cirrhosis of the
liver and to increased risk for hepatitis and cancer. Alcohol consumption during pregnancy can result in low
birth weight, fetal alcoholism, and other damage to the
fetus. While there are clear risks associated with excessive alcohol consumption, the dietary guidelines indicate
that alcohol used in moderation can enhance enjoyment
of meals and reduce risks for coronary heart disease.
336
Section 5 ▶ Nutrition and Body Composition
Follow the recommendations to assure healthy
amounts of water and other fluids in the diet. The
following list includes basic recommendations for water
and other fluids in the diet:
Start
here
Amount Per Serving
Calories 250
• In addition to foods containing water, the average
adult needs about eight glasses (8 ounces each) of
water every day. Active people and those who exercise
in hot environments require additional water.
Calories from Fat 110
% Daily Value*
Limit
these
nutrients
• Coffee, tea, and soft drinks should not be substituted
for sources of key nutrients, such as low-fat milk, fruit
juices, or foods rich in calcium.
• Limit daily servings of beverages containing caffeine
to no more than three.
• Limit sugared soft drinks.
• If you are an adult and you choose to drink alcohol, do
so in moderation. The dietary guidelines for Americans indicate that moderation means no more than
one drink per day for women and no more than two
drinks per day for men (one drink equals 12 ounces
of regular beer, 5 ounces of wine [small glass], or one
average-size cocktail [1.5 ounces of 80-proof alcohol]).
Serving Size 1 cup (228g)
Servings Per Container 2
W
R
I
G
H
T
,
Get
enough
of these
nutrients
Footnote
18%
15%
Total Fat 12g
Saturated Fat 3g
Trans Fat 1.5g
Cholesterol 30mg
Sodium 470mg
Total Carbohydrate 31g
Dietary Fiber 0g
Sugars 5g
Protein 5g
10%
20%
10%
0%
Vitamin A
Vitamin C
Calcium
Iron
4%
2%
20%
4%
* Percent Daily Values are based on a 2,000 calorie diet.
Your Daily Values may be higher or lower depending on
your calorie needs.
Calories:
2,000
2,500
80g
Less than
65g
Total Fat
25g
Less than
20g
Sat Fat
300mg
300mg
Less than
Cholesterol
2400mg
Less than
2,400mg
Sodium
375g
300g
Total Carbohydrate
30g
25g
Dietary Fiber
Figure 4 ▶ Sample food label for macaroni and cheese.
Making Well-Informed
Food Choices
Well-informed consumers eat better. Most people
underestimate the number of calories they consume daily
and the caloric content of specific foods. Not surprisingly, people who are better informed about the content
of their food are more likely to make wise food choices.
Ways to get better food choice information include accurate food labels on packages and information about food
content on menus or signs in restaurants.
The content of food labels changes from time to time
depending on federal guidelines and policies. The most
recent change is the requirement to post trans fat content
on labels (see Figure 4). This action was prompted by the
clear scientific evidence that trans fats are more likely
to cause atherosclerosis and heart disease than are other
types of fat. Trans fats are discussed in a later section.
Reading food labels helps you be more aware of what
you are eating and make healthier choices in your daily
eating. In particular, paying attention to the amounts of
saturated fat, trans fat, and cholesterol posted on food
labels helps you make heart-healthy
food choices. When comparing
similar food products, combine the
VIDEO 4
grams (g) of saturated fat and trans
fat and look for the lowest combined amount. The listing
of % Daily Value (% DV) can also be useful. Foods low in
saturated fat and cholesterol generally have % DV values
less than 5 percent, while foods high in saturated fat and
cholesterol have values greater than 20 percent.
Source: U.S. Food and Drug Administration.
S
H
Supplemental food labels may not provide accurate
E
information.
Some manufacturers have used supplementalRlabels on foods to advertise healthy aspects of their
products. An example is the “Smart Choice” designation
R by a consortium of food manufacturers. The labels
created
were
Y placed prominently on the front of selected food
packages to promote them as a healthy choice for good
nutrition. While perhaps well-intentioned, the claims and
designations
were not approved by the FDA and could
2
have swayed consumers to select the product. National
7
nutrition groups criticized the name (Smart Choice) as
9 as the location and content of the labels. This action
well
prompted the FDA to require manufacturers to cease
3
using the potentially confusing labels. Care should be
B when considering claims on food packages.
taken
U
Guides to food contents in restaurants can help
consumers eat better. It is increasingly common for
restaurants to post the calorie counts for the foods on
their menu. Some restaurants also provide more detailed
information about specific nutrients (e.g., protein, carbohydrate, salt, fiber). These changes have come about due,
in part, to policy changes and USDA requirements; however, they also reflect an increased consumer demand for
health and nutrition information. While some restaurants
still emphasize gluttony and excess in advertisements and
menus, there are many others that are positioning themselves to accommodate greater demand for healthier food
Concept 14 ▶ Nutrition
Health is available to Everyone for a
Lifetime, and it’s Personal
TECHNOLOGY UPDATE
Vending Machines to Provide
Nutrition Information
Food labels are required on all food products, but consumers do not have access to this information when
selecting foods from most vending machines. According
to an industry organization, over 100 million Americans
use a vending machine each day. Legislation in Congress
may soon require vending companies to provide nutrition information so that consumers have the opportunity to make healthier food choices at these machines.
Companies that make vending machines have developed machines to make it easy for consumers to view
this information, so the technology is already available.
Some vending groups are concerned that people may be
less inclined to buy snacks from vending machines if they
look at the nutritional content. However, this is the whole
point of the proposed policy.
Do you think these high-tech vending machines will influence
decisions about food purchases?
ACTIVITY
W
R
I
G
H
T
,
S
choices. Posting the nutritional quality of foods allows
H
restaurants to at least document that they have provided
E
consumers with the information needed to make healthier choices.
R
Sound Eating Practices
337
R
Y
Consistent eating patterns (with a daily breakfast)
are important for good nutrition. Eating regular
2
meals every day, including a good breakfast, is wise. Many
7
studies have shown breakfast to be an important meal,
9
in which one-fourth of the day’s calories should be consumed. Skipping breakfast impairs performance because
3
blood sugar levels drop in the long period between dinB
ner the night before and lunch the following day. Eating
every 4 to 6 hours is wise.
U
Moderation is a good general rule of nutrition. You
do not have to permanently eliminate foods that you
really enjoy, but some of your favorite foods may not
be among the best choices. Enjoying special foods on
occasion is part of moderation. The key is to limit food
choices high in empty calories.
Portion sizes have increased in recent years. Cafeteriastyle restaurants (and others) sometimes offer all you
can eat meals, which encourage larger portions. Reducing portion size is very important when eating out and at
home (see Concept 15 for more information).
Food safety is an important public health concern.
Almost every year there are tragic reports of food-related
illnesses and deaths caused by infections from such
bacteria as Salmonella or Listeria. In 2010, an outbreak
of Salmonella in eggs sickened over 1,500 people. A
more recent outbreak of Salmonella from contaminated
ground turkey killed 1 person and sickened 111 others.
The most tragic and publicized food safety issue was an
outbreak of Listeria traced to contaminated cantaloupes
that killed 29 people and sickened over 130 others from
28 states. The CDC has indicated that the incidence of
infection has actually come down 23 percent over the
past 15 to 20 years, but news of food contamination
always creates headlines.
Do outbreaks of food-related diseases concern you? Do they
influence your decisions about buying certain types of foods?
ACTIVITY
Minimize your reliance on fast foods. Recent estimates suggest that 63 percent of Americans eat fast food
one to three times a week and an additional 3 percent eat
fast food three to five times a week. Unfortunately, many
fast foods are poor nutritional choices. Hamburgers are
usually high in fat, as are french fries
(because they are usually cooked in
saturated fat). Even chicken and fish
VIDEO 5
are often high in fat and calories
because they may be cooked in fat and covered with high-fat/
high-calorie sauces. (Fast foods are also discussed in more
detail in Concept 15.)
Healthy snacks can be an important part of good
nutrition. For people who want to lose weight or maintain their current weight, small snacks of appropriate
foods can help fool the appetite. For people wanting to
gain weight, snacks provide additional calories. The calories consumed in snacks will probably necessitate limiting
the calories from meals. The key is proper selection of
the foods for snacking.
As with your total diet, the best snacks are nutritionally
dense. Too many snacks are high in calories, fats, simple
sugar, and salt. Even foods sold as “healthy snacks,” such as
granola bars, are often high in fat and simple sugar. Some
common snacks, such as chips, pretzels, and even popcorn,
may be high in salt and may be cooked in fat. Healthier
snacks include ice milk (instead of ice cream), fresh fruits,
vegetable sticks, popcorn not cooked in fat and with little
or no salt, crackers, and nuts with little or no salt.
338
Section 5 ▶ Nutrition and Body Composition
A CLOSER LOOK
MyPlate
Plate
e “Supe
“SuperTracker”
SuperTr
for Diet and
Activity Monitoring
Self-monitoring is an important behavioral skill for adopting and maintaining healthy lifestyles. There are many
cell phone apps and resources for monitoring your diet,
but the web-based resources available through MyPlate
provide a free, comprehensive set of tools (called SuperTracker). An easy-to-use food database (Food-A-Pedia)
allows you to enter the name of a specific food and get
quick feedback concerning the food’s content. A customized tool called the Food Tracker evaluates the nutrient quality of your diet and an accompanying Physical
Activity Tracker evaluates activity levels compared to
the U.S. Physical Activity Guidelines. An integrative tool
(My Weight Manager) combines data on energy intake
and expenditure to facilitate weight management. Companion tools let you set goals, use virtual coaches, and
monitor progress over time. The comprehensive set of
self-monitoring tools can assist consumers in adopting
and maintaining a healthy and active lifestyle.
How would your diet stack up to the 2010 Dietary Guidelines?
Would you benefit from tools designed to evaluate and track the
quality of your diet over time?
ACTIVITY
Minimize your consumption of overly processed
foods and foods high in hydrogenated fat or
saturated fat. Many foods available in grocery stores
have been highly processed to enhance shelf life and
Table 4 ▶ Comparing the Quality of Similar Food Products
convenience. In many cases, the processing of foods
removes valuable nutrients and includes other additives that may compromise overall nutrition. Processing
of grains, for example, typically removes the bran and
germ layers, which contain fiber and valuable minerals.
In regard to additives, there has been considerable attention on the possible negative effects of high fructose
corn syrup, as well as the pervasive use of hydrogenated
vegetable oils containing trans fatty acids. Table 4 compares food quality in each of the main food categories.
To improve your diet, you should aim to choose foods in
the “more desirable” category instead of those in the “less
desirable” category.
Consider
eating organic foods to reduce exposure
W
to carcinogens. Consumers are often confused about
R
what “organic” means. Organic food differs from convenI
tionally
produced food primarily in the way it is grown,
handled, and processed. Organic food is produced withG
out conventional pesticides and using natural fertilizers.
H
Organic
meat, poultry, eggs, and dairy products come
from
animals
that are given no antibiotics or growth horT
mones. Organic foods are typically produced by farmers
, emphasize the use of renewable resources and the
who
conservation of soil and water. The benefits of organic
farming production have led to initiatives to encourage
S to adopt organic practices.
farmers
HThe U.S. Department of Agriculture (USDA) has
recently established a new set of standards for foods
E as “organic.” The current labeling requires that
labeled
aR
government-approved certifier inspect the farm where
the food is grown or produced to ensure that the farmer
R
is following all the rules necessary to meet USDA organic
Y
2
7
9
3
B
U
Food Product
Less Desirable Option
More Desirable
Option
Bread
White bread
Whole wheat bread
Rice
White rice
Brown rice
Juice
Sweetened juice
100% juice
Fruit
Canned
Fresh
More vitamins, more fiber, less sugar
Vegetables
Canned
Fresh
More vitamins, less salt
Potatoes
French fries
Baked potato
Less saturated fat
Milk
2% milk
Skim milk
Less saturated fat
Meat
Ground beef (high fat)
Ground sirloin (low fat)
Less saturated fat
Oils
Vegetable oil
Canola oil
More monounsaturated fat
Snack food
Fried chips
Baked chips
Less fat/calorie content, less trans fat
Benefit of More Desirable Option in Nutrition Quality
More fiber
More fiber
More fiber and less fructose corn syrup
Concept 14 ▶ Nutrition
339
In the News
Knowledge Doesn’t Translate to Behavior
K
N
Nutrition
remains a top priority for most Americans. A Harris poll found that awareness of
ic
key nutritional facts is high. At least three-quarters of all U.S.
adults place importance on freshness (89 percent), fiber (81
percent), and whole grains (81 percent) when choosing foods.
Consumers also carefully consider the fat content (80 percent),
portion size (79 percent), calorie content (77 percent), and saturated fat (76 percent) when making food and beverage purchases. Over half of U.S. adults (57 percent) report monitoring
or restricting consumption of some foods to improve their diet.
Sugar and salt are the top two restricted items, with 34 percent
and 32 percent restricting salt and sugar, respectively.
While awareness is high, it does not appear to translate into
dietary change for most segments of the population. Fewer
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T
,
standards. Companies that handle, process, or sell organic
food must also be certified. The USDA does not imply
that organically produced food is safer or more nutritious
S
than conventionally produced food, but many health
H
experts recommend organic foods to reduce exposure
to pesticides and other chemicals and to help support
E
more sustainable and environmentally friendly agriculR
tural practices. Foods purchased at local farmer’s markets
may claim to be organic but may or may not meet FDA
R
standards.
Y
Nutrition and Physical
Performance
2
7
9
Some basic dietary guidelines exist for active people.
In general, the nutrition rules described in this concept
3
apply to all people, whether active or sedentary, but some
B
additional nutrition facts are important for exercisers
and athletes. Because active people often expend calories
U
in amounts considerably above normal, they need extra
calories in their diet. To avoid excess fat and protein,
complex carbohydrates should constitute as much as 70
percent of total caloric intake. A higher amount of protein is generally recommended for active individuals (1.2
grams per kg of body weight) because some protein is
used as an energy source during exercise. Extra protein
is obtained in the additional calories consumed. While
the IOM range of 10 to 35 percent allows a “broader
range” of choice, intake above 15 percent is not typically
necessary.
than half of Americans who rated sugar or salt as “important
when managing their diet/weight” actually restrict their sugar
(42 percent) or salt (47 percent) intake. Adherence to diet recommendations varies across the generations. Respondents
over age 66 were the most likely to pay close attention to
nutritional facts and translate their health consciousness into
behavior. This was attributed to the greater need to follow a
diet with specific restrictions. Overall, the results suggest that
adherence to diet recommendations may be more driven by
necessity than by knowledge.
Does your knowledge and awareness of nutrition directly impact
your food choices?
ACTIVITY
Carbohydrate loading before exercise and carbohydrate replacement during exercise can enhance
sustained aerobic performances. Athletes and vigorously active people must maintain a high level of readily
available fuel, especially in the muscles. Consumption of
complex carbohydrates is the best way to assure this.
Prior to an activity requiring an extended duration of
physical performance (more than 1 hour in length, such
as a marathon), carbohydrate loading can be useful.
Carbohydrate loading is accomplished by resting 1 or 2
days before the event and eating a higher than normal
amount of complex carbohydrates. This helps build up
maximum levels of stored carbohydrate (glycogen) in the
muscles and liver so it can be used during exercise. The
key in carbohydrate loading is not to eat a lot but, rather,
to eat a higher percentage of carbohydrates than normal.
Ingesting carbohydrate beverages during sustained
exercise can also aid performance by preventing or forestalling muscle glycogen depletion. Fluid-replacement
drinks containing 6 to 8 percent carbohydrates and no
more than 6 to 8 percent sugar are very helpful in preventing dehydration and replacing energy stores. A number
Carbohydrate Loading The extra consumption of
complex carbohydrates in the days prior to sustained
performance.
Glycogen A source of energy stored in the
muscles and liver necessary for sustained physical
activity.
340
Section 5 ▶ Nutrition and Body Composition
they are not recommended for individuals primarily
interested in weight control.
The timing may be more important than the makeup
of a pre-event meal. If you are racing or doing highlevel exercise early in the morning, eat a small meal prior
to starting. Eat about 3 hours before competition or
heavy exercise to allow time for digestion. Generally, athletes can select foods on the basis of experience, but easily digested carbohydrates are best. Generally, fat intake
should be minimal because fat digests more slowly; proteins and high-cellulose foods should be kept to a moderate amount prior to prolonged events to avoid urinary
and bowel excretion. Drinking 2 or 3 cups of liquid will
ensure
W adequate hydration.
Consuming simple carbohydrates (sugar, candy) within
anRhour or two of an event is not recommended because it
may
I cause an insulin response, resulting in weakness and
fatigue, or it may cause stomach distress, cramps, or nausea.
G
H
Changes
in the frequency and composition of
meals
are
important to gain muscle mass. To
T
increase muscle mass, the body requires a greater caloric
,
intake.
The challenge is to provide enough extra caloGood nutrition is essential for active people.
of companies also make concentrated carbohydrate gels
that deliver carbohydrates (generally 80 percent complex,
20 percent simple) in a form the body can absorb quickly
for energy. Examples are PowerGel and Gu. Energy bars,
such as Powerbars and Clif bars, are also commonly eaten
during or after exercise to enhance energy stores. The
various carbohydrate supplements have been shown to be
effective for exercise sessions lasting over an hour and are
good for replacing glycogen stores after exercise. Consuming carbohydrates 15 to 30 minutes following exercise
can aid in rapid replenishment of muscle glycogen, which
may enhance future performance or training sessions.
These supplements have little benefit for shorter bouts
of exercise. Because they contain considerable calories,
ries for the muscle without excess amounts going to fat.
An increase of 500 to 1,000 calories a day will help most
S
people gain muscle mass over time. Smaller, more frequent
H meals are best for weight gain, since they tend to
keep the metabolic rate high. The majority of extra caloE
ries should come from complex carbohydrates. Breads,
R rice, and fruits such as bananas are good sources.
pasta,
Granola,
nuts, juices (grape and cranberry), and milk also
R
make good high-calorie, healthy snacks.
YDiet supplements are not particularly effective unless
used as part of a behaviorally based program. High-fat
diets can result in weight gain but may not be best for
2 health, especially if they are high in saturated fat.
good
If7weight gain does not occur over a period of weeks and
months with extra calorie consumption, individuals may
9 to seek medical assistance.
need
3
B
U
Strategies for Action
An analysis of your current diet is
a good first step in making future
decisions about what you eat. Many experts recommend
keeping a log of what you eat over an extended period so you
can determine the overall quality of your diet. In Lab 14A, you
will have an opportunity to track your diet over several days. In
addition to computing the amount of carbohydrates, fats, and
proteins, you will also be able to monitor your consumption of
fruits and vegetables. A number of online tools and personal
software programs can make dietary calculations for you
and provide a more comprehensive report of nutrient intake.
Whether you use a Web-based tool or a paper and pencil log
doesn’t really matter—the key is to monitor and evaluate the
quality of your diet.
Concept 14 ▶ Nutrition
Making small changes in diet patterns can have a big
impact. Nutrition experts emphasize the importance of
making small changes in your diet over time rather than trying to make comprehensive changes at one time. Try cutting
back on sweets or soda. Simply adding a bit more fruit and
vegetables to your diet can lead to major changes in overall
341
diet quality. In Lab 14B, you will be given the opportunity to
compare a “nutritious diet” to a “favorite diet.” Analyzing two
daily meal plans will help you get a more accurate picture as
to whether foods you think are nutritious actually meet current
healthy lifestyle goals.
ACTIVITY
Web Resources
American Dietetic Association www.eatright.org
Berkeley Nutrition Services www.nutritionquest.com
Center for Nutrition Policy and Promotion www.usda
.gov/cnpp
Center for Science in the Public Interest www.cspinet.org
FDA Food Website www.fda.gov/Food/default.htm
Food and Drug Administration (FDA) www.fda.gov
Food Safety Database www.foodsafety.gov
Institute of Medicine www.iom.edu
Institute of Medicine—Food and Nutrition www.iom
.edu/Global/Topics/Food-Nutrition.aspx
International Food Information Council Foundation
www.ific.org
MyPlate www.choosemyplate.gov
MyPlate Food-A-Pedia www.choosemyplate
.gov/SuperTracker/foodapedia.aspx
MyPlate SuperTracker www.choosemyplate
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.gov/SuperTracker/foodtracker.aspx
National Nutrition Summit Database www.nlm.nih
.gov/pubs/cbm/nutritionsummit.html
Nutrition.gov www.nutrition.gov
Office of Dietary Supplements http://ods.od.nih.gov
Rudd Center for Food Policy and Obesity (Yale University)
www.yaleruddcenter.org
U.S. Department of Agriculture (USDA) www.usda.gov
USDA Food and Nutrition Information Center www
.nal.usda.gov/fnic
USDA MyFoodapedia (calorie calculator) http://fnic
.nal.usda.gov/dietary-guidance/interactive-tools/
calculators-and-counters
2
7
9
3
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Suggested Readings
Dunford, M. 2010. Fundamentals of Sport and Exercise Nutrition.
Champaign, IL: Human Kinetics.
Finkelstein, E. A., and L. Zuckerman. 2008. The Fattening of
America. Hoboken, NJ: John Wiley and Sons.
Gardener, H., et al. 2012. Mediterranean diet and white matter
hyperintensity volume in the Northern Manhattan Study.
Archives of Neurology 69(2):251–256.
Institute of Medicine, Food and Nutrition Board. 2010. Strategies to Reduce Sodium Intake in the United States. Washington,
DC: National Academies Press.
Johnson, R. K., et al. 2009. Dietary sugars intake and cardiovascular health: A scientific statement from the American
Heart Association. Circulation 120(11):1011–1020.
Kessler, D. 2009. The End of Overeating: Taking Control of the
Insatiable American Appetite. New York: Rodale Press.
Otten, J. J., Helwig, J. P., and L. D. Meyers (Eds.). 2006.
Dietary Referenced Intakes: The Essential Guide to Nutrient Requirements. Washington, DC: Institute of Medicine,
National Academy of Science Press.
Pan, A., et al. 2012. Red meat consumption and mortality:
Results from 2 prospective cohort studies. American Journal
of Public Health 100(2):312–318.
Roberto, C. A., et al. 2010. Evaluating the impact of menu
labeling on food choices and intake. American Journal of
Public Health 100(2):312–318.
Wardlaw, G. M. 2011. Contemporary Nutrition. New York:
McGraw-Hill Higher Education.
342
Section 5 ▶ Nutrition and Body Composition
Healthy People
2020
The objectives listed below are societal goals designed to help
all Americans improve their health between now and the year
2020. They were selected because they relate to the content
of this concept.
• Increase the contribution of fruits in the diet.
• Increase the variety and contribution of vegetables
in the diet.
• Increase the contribution of whole grains in the diet.
• Reduce consumption of saturated fat in the diet.
• Reduce consumption of sodium.
• Increase consumption of calcium.
• Reduce iron deficiency.
A national goal is to increase fruit and vegetables in the diet. This is
information children learn in elementary school, yet many Americans
fail to meet the guideline that “half of the plate should be fruits and
vegetables.” What can be done to change the pattern of eating so
that more people eat adequate fruits and vegetables?
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ACTIVITY
Lab 14A Nutrition Analysis
Section
Lab 14A
Name
Date
Purpose: To learn to keep a dietary log, to determine the nutritional quality of your diet, to determine your average
daily caloric intake, and to determine necessary changes in eating habits
Procedures
,
Results
Record the number of calories consumed for each of the 2 days.
S
H calories
E your diet as recorded in this lab. Explain any changes
Conclusions and Implications: In several sentences, discuss
in your eating habits that may be necessary. Comment on whether
R the days you surveyed are typical of your normal diet.
R
Y
Weekday
calories
Weekend
2
7
9
3
B
U
343
Nutrition Analysis
1. Record your dietary intake for 2 days using the Daily Diet Record sheets (see pages 345–346). Record intake for
1 weekday and 1 weekend day. You may wish to make copies of the record sheet for future use.
2. Include the actual foods eaten and the amount (size of portion in teaspoons, tablespoons, cups, ounces, or other
standard units of measurement). Be sure to include all drinks (coffee, tea, soft drinks, etc.). Include all foods eaten,
W
including sauces, gravies, dressings, toppings, spreads, and so on. Determine your caloric consumption for each
Rwebsite to assist in evaluating your diet.
of the 2 days. Use the calorie guides at the myplate.gov
3. List the number of servings from each food group by each food choice.
I
4. Estimate the proportion of complex carbohydrate, simple carbohydrate, protein, and fat in each meal and in
G
snacks, as well as for the total day.
5. Answer the questions in Chart 1 on page 344, using information
for a typical day based on the Daily Diet Record
H
sheets. Score 1 point for each “yes” answer. Then use Chart 2 to rate your dietary habits (circle rating).
6. Complete the Conclusions and Implications sections T
Lab 14A
Chart 1 Dietary Habits Questionnaire
Yes
No
Answer questions based on a typical day (use your Daily Diet Records to help).
1. Do you eat at least three healthy meals each day?
2. Do you eat a healthy breakfast?
3. Do you eat lunch regularly?
Nutrition Analysis
4. Does your diet contain 45 to 65 percent carbohydrates with a high concentration of fiber?*
5. Are less than one-fourth of the carbohydrates you eat simple carbohydrates?
6. Does your diet contain 10 to 35 percent protein?*
W
R
8. Do you limit the amount of saturated fat in your diet (no more than 10 percent)?
I
9. Do you limit salt intake to acceptable amounts?
G
H diet without a supplement?
10. Do you get adequate amounts of vitamins in your
T
11. Do you typically eat 6 to 11 servings from the bread, cereal, rice, and pasta group of foods?
,
7. Does your diet contain 20 to 35 percent fat?*
12. Do you typically eat 3 to 5 servings of vegetables?
S
14. Do you typically eat 2 to 3 servings from the milk,
H yogurt, and cheese group of foods?
E poultry, fish, beans, eggs, and nuts group of foods?
15. Do you typically eat 2 to 3 servings from the meat,
R
16. Do you drink adequate amounts of water?
R
17. Do you get adequate minerals in your diet without a supplement?
Y
13. Do you typically eat 2 to 4 servings of fruits?
18. Do you limit your caffeine and alcohol consumption to acceptable levels?
2
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19. Is your average caloric consumption reasonable for your body size and for the amount of calories you
normally expend?
Total number of “yes” answers
*Based on USDA standards.
Chart 2 Dietary Habits Rating Scale
Score
Rating
18–19
Very good
15–17
Good
13–14
Marginal
12 or less
344
Poor
Daily Diet Record
Day 1
Breakfast Food
Calories
Food Servings
Bread/Cereal Fruit/Veg. Milk/Meat Fat/Sweet
Estimated Meal
Calories %
% Protein
% Fat
% Complex
carbohydrate
Lab 14A
Amount
(cups, tsp., etc.)
% Simple
carbohydrate
Meal Total
Lunch Food
Meal Total
Dinner Food
Amount
(cups, tsp., etc.)
Amount
(cups, tsp., etc.)
Calories
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Calories
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Bread/Cereal
Meal Total
Snack Food
Amount
(cups, tsp., etc.)
Food Servings
Bread/Cereal Fruit/Veg. Milk/Meat Fat/Sweet
Calories
2
7
9
3
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Bread/Cereal
Estimated Meal
Calories %
% Protein
% Fat
% Complex
carbohydrate
% Simple
carbohydrate
100% Total
Food Servings
Fruit/Veg. Milk/Meat Fat/Sweet
Estimated Meal
Calories %
% Protein
% Fat
% Complex
carbohydrate
% Simple
carbohydrate
100% Total
Food Servings
Fruit/Veg. Milk/Meat Fat/Sweet
Estimated Snack
Calories %
% Protein
% Fat
% Complex
carbohydrate
% Simple
carbohydrate
100% Total
Estimated Daily
Total Calories %
Meal Total
Daily Totals
Calories
Servings
Servings
Servings
Servings
% Protein
% Fat
% Complex
carbohydrate
% Simple
carbohydrate
100% Total
345
Nutrition Analysis
100% Total
Daily Diet Record
Day 2
Lab 14A
Breakfast Food
Amount
(cups, tsp., etc.)
Calories
Food Servings
Bread/Cereal Fruit/Veg. Milk/Meat Fat/Sweet
Estimated Meal
Calories %
% Protein
% Fat
% Complex
carbohydrate
Nutrition Analysis
% Simple
carbohydrate
100% Total
Meal Total
Lunch Food
Meal Total
Dinner Food
Amount
(cups, tsp., etc.)
Amount
(cups, tsp., etc.)
Calories
Food Servings
Bread/Cereal Fruit/Veg. Milk/Meat Fat/Sweet
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Calories
S
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Bread/Cereal
Estimated Meal
Calories %
% Protein
% Fat
% Complex
carbohydrate
% Simple
carbohydrate
100% Total
Food Servings
Fruit/Veg. Milk/Meat Fat/Sweet
Estimated Meal
Calories %
% Protein
% Fat
% Complex
carbohydrate
% Simple
carbohydrate
100% Total
Meal Total
Snack Food
Amount
(cups, tsp., etc.)
Calories
2
Bread/Cereal
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9
3
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Food Servings
Fruit/Veg. Milk/Meat Fat/Sweet
Estimated Snack
Calories %
% Protein
% Fat
% Complex
carbohydrate
% Simple
carbohydrate
100% Total
Meal Total
Estimated Daily
Total Calories %
Daily Totals
% Protein
% Fat
Calories
Servings
Servings
Servings
Servings
% Complex
carbohydrate
% Simple
carbohydrate
100% Total
346
Lab 14B Selecting Nutritious Foods
Section
Lab 14B
Name
Date
Purpose: To learn to select a nutritious diet, to determine the nutritive value of favorite foods, and to compare
nutritious and favorite foods in terms of nutrient content
Procedures
T
Results: Record your results below. Calculate percentage, of calories from each source by dividing total calories into
calories from each food source (protein, carbohydrates, or fat).
Food Selection Results
Source
Protein
Carbohydrates
Calories
S
H
Favorite Foods
E
% of Total Calories
R
R
Y
Calories
Nutritious Foods
% of Total Calories
Fat
2
100%
7
9
Conclusions and Implications: In several sentences, discuss the differences you found between your nutritious diet
3 as well as other things you learned from doing this lab.
and your favorite diet. Discuss the quality of your nutritious diet
B
U
Total 100%
100%
347
Selecting Nutritious Foods
1. Select a favorite breakfast, lunch, and dinner from the foods list in Appendix C. Include between-meal snacks with
the nearest meal. If you cannot find foods you would normally choose, select those most similar to choices you
might make.
2. Select a breakfast, lunch, and dinner from foods you feel would make the most nutritious meals. Include
W
between-meal snacks with the nearest meal.
3. Record your “favorite foods” and “nutritious foods” onR
page 348. Record the calories for proteins, carbohydrates,
and fats for each of the foods you choose.
I
4. Total each column for the “favorite” and the “nutritious” meals.
G protein, carbohydrate, and fat by dividing each column
5. Determine the percentages of your total calories that are
total by the total number of calories consumed.
H
6. Comment on what you learned in the Conclusions and Implications section.
“Favorite” versus “Nutritious” Food Choices for Three Daily Meals
Selecting Nutritious Foods
Lab 14B
Breakfast Favorite
Food
Food Choices
Cal.
Pro.
Cal.
Car.
Cal.
Breakfast Nutritious
Fat
Cal.
Totals
Food Choices
Cal.
Pro.
Cal.
Car.
Cal.
Fat
Cal.
Dinner Favorite
Food Choices
Car.
Cal.
Fat
Cal.
Food Choices
Cal.
Cal.
Pro.
Cal.
Car.
Cal.
2
7
Food
9
3
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Dinner Nutritious
Fat
Cal.
Totals
Totals
Daily Totals (Calories)
Daily Totals (Calories)
Daily % of Total Calories
Daily % of Total Calories
348
Pro.
Cal.
Pro.
Cal.
Car.
Cal.
Fat
Cal.
S
H
E
R
R
Y
Totals
Totals
Food
W
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G Nutritious
Lunch
H
Food
T
,
Cal.
Totals
Lunch Favorite
Food
Food
Food Choices
Food Choices
Cal.
Pro.
Cal.
Car.
Cal.
Fat
Cal.
Managing Diet and Activity
for Healthy Body Fatness
LEARNING OBJECTIVES
After completing the study of this concept, you will be able to:
▶ Explain the principles for weight control and the concept of energy balance.
▶ Identify the features of an obesogenic environment that influence our behavior.
▶ Outline guidelines for weight loss treatments. W
▶ Describe and apply, when appropriate, guidelinesR
for losing body fat.
▶ Utilize healthy shopping
and eating strategies and
guidelines.
Various management strategies
for eating and performing
physical activity are useful
in achieving and maintaining
optimal body composition.
Concept 15
▶ Evaluate fast-food options.
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349
350
Section 5 ▶ Nutrition and Body Composition
he fact that more than 67 percent of adult Americans
are classified as overweight is clear evidence that
weight control is a vexing problem for the majority of
the population. Most recognize the importance of the
problem and want to correct it. In fact, a recent national
survey by the International Food Information Council
(IFIC) reported that nearly two-thirds of Americans were
either very concerned or somewhat concerned about
their weight.
Too often, the focus is on appearance rather than
health and on weight loss rather than fat loss. In attempts
to lose weight, the dietary (energy intake) side of the
energy balance equation is typically emphasized. However, the energy expenditure side of the equation is just as
important, if not more so. Despite the documented benefits, few people trying to lose weight are physically active.
A state-based survey determined that approximately onehalf of individuals trying to lose weight do not engage
in any physical activity, and only 15 percent report exercising regularly. The challenges many people experience with weight control may be an indirect reflection
of the challenges people face in trying to be more active.
Although being physically active cannot ensure you will
become as thin as you desire, you may attain a body size
that is appropriate for your genetics and body type.
The focus in this concept is on lifestyle patterns (both
diet and physical activity) that will assist with losing
body fat rather than weight. Guidelines for maintaining
healthy body fat levels over time are also presented.
T
Factors Influencing Weight
and Fat Control
Long-term weight control requires a balance
between energy intake and energy expenditure.
The relationships governing energy balance are very
simple—the number of calories expended must match the
number consumed. There may be subtle differences on a
daily basis, but if intake exceeds expenditure over a period
of time, a person will store the extra calories as body fat.
The average person gains 1 pound of weight (i.e., fat) for
every year over the age of 25. This may sound like a lot but
it represents a calorie difference of only 10 kcal per day
(approximately the calories found in a cracker or potato
chip). This subtle difference shows the precise regulation
of intake and expenditure that is normally in effect when
a person maintains his or her body weight. The built-in
regulation system is based on our appetite, which guides
us when we might be running low on energy.
Figure 1 shows the hypothetical balance between
energy intake and expenditure. Energy intake comes
from the three major nutrients in our diet (carbohydrates, fats, and proteins) as well as from alcohol. Energy
expenditure can be divided into three major components
as well. Basal metabolism accounts for the bulk of daily
energy expenditure (60 percent to 75 percent) and this
refers to the calories expended to maintain basic body
functions while the body is at rest. A second category,
called thermogenesis, captures the energy expended processing the food we eat (approximately 10 percent of total
daily energy expenditure). The third and most variable
component of energy expenditure rate is physical activity
(typically accounting for 10 to 30 percent of total energy
expenditure in most people). To maintain a healthy
weight, a person’s overall energy expenditure must offset
energy intake. While it is difficult to
monitor these directly, the body has
built-in
VIDEO 1
W regulatory systems that help
in weight regulation. Detailed covR of these pathways is beyond the scope of the book,
erage
but
I the most important part of the system is your appetite because it helps prompt and influence eating.
G
H
Physical
activity contributes to energy balance in a
number of ways. By maintaining an active lifestyle, you
T
can burn off extra calories, keep your body’s metabolism
, and prevent the decline in basal metabolic rate that
high,
typically occurs with aging (due to reduced muscle mass).
All types of physical activity from the physical activity
S
pyramid
can be beneficial to weight control. Moderate
physical
activity
(see Concept 6) is especially effective
H
because people of all ages and abilities can perform it. It
E be maintained for long periods of time and results in
can
significant
calorie expenditure. Long-term studies show
R
that 60 or more minutes of moderate activity such as
R is very effective for long-term weight loss and
walking
maintenance.
Y
Vigorous physical activity (see Concepts 7 and 8) can
also be effective in maintaining or losing weight. For some
people,
2 especially older adults, vigorous activity may be
more difficult to adhere to over a long time. However, for
7
9
3
B
U
Energy
intake
Energy
expenditure
Protein
Physical activity
Fats
Thermogenesis
Carbohydrates
Basal metabolism
Figure 1 ▶ Components of energy intake must balance
components of energy expenditure for weight maintenance.
Concept 15 ▶ Managing Diet and Activity for Healthy Body Fatness
those who stick with it, vigorous activity expends more
calories in a shorter time, and for this reason, it can be
a very good way to expend calories. Research shows that
bouts of vigorous physical activity can lead to increases
in basal metabolic rate that persist throughout the day.
Therefore, vigorous activity can contribute to additional
energy expenditure after the workout is done. There is
now considerable evidence showing that muscle fitness
exercise also contributes to maintaining a healthy body
weight (see Concept 9). Muscle fitness exercise expends
calories and increases muscle mass, leading to an increase
in calories expended at rest. Flexibility exercises (see
Concept 10) also expend calories, but are of lower intensity than other types of activities on the pyramid. They
can still contribute to energy expenditure, however.
W
R
The accumulation of light physical activity can help
burn extra calories. Most of the emphasis in this book
I
has been on moderate and vigorous forms of physical activG
ity. As described in Concept 6, “light” physical activity falls
H
between rest and moderate physical activity on the energy
expenditure continuum (1.5 to 3 METS). Research indiT
cates that light activities may help reduce risks associated
,
with excessive time spent being sedentary (e.g., sitting). The
accumulation of light activity can also contribute to weight
control by burning more calories. Researchers coined the
S
term NEAT (non-exercise activity thermogenesis) to refer
to the accumulation of activity from low-intensity moveH
ments throughout the day. Light activity may account for
Health is available to Everyone for a
Lifetime, and it’s Personal
A survey by the International Food Information Council
reports that only 9 percent of people in the United States
know the approximate number of calories they should
eat in a day. About 9 percent report actually tracking
their calories on a daily basis. Calorie requirements are
unique to each person and are influenced by your gender, age, body size, and physical activity level. Typical
ranges for a small sedentary woman may be 1,400 to
1,600 or 2,000 to 2,200 for a sedentary man. Our body
has a natural ability to regulate intake (appetite) but
people tend to disregard it or not pay attention to the
cues. Some experts are concerned about the lack of
awareness about calorie requirements. For example, if
you knew your calorie requirement was 1,600 calories a
day you may think twice about eating a burger and fries
that contain 1,200 calories at one meal.
What steps can you take to make sure that you do not exceed
recommended daily calorie requirements for your age, gender,
and activity level?
ACTIVITY
E
R
R
Y
2
7
9
3
B
U
351
as little as 15 percent of total daily energy expenditure in
sedentary people and up to 50 percent in people with more
active jobs and lifestyles. The weight maintenance benefits
of light or NEAT activity are greatest when the activities
replace sedentary activities such as sitting (e.g., TV watching and computer use). To further take advantage of NEAT,
many people have started using active workstations that
allow them to walk slowly on a treadmill or lightly pedal a
bike while working at a computer.
Awareness and dietary restraint are needed to
avoid excess caloric intake. In our modern society, it
is very easy for people to meet their daily energy needs.
In fact, considerable willpower is needed to keep energy
intake at a manageable level. Having an extra cookie or
brownie for a snack may sound like a good idea until you
realize you would need to possibly walk between one and
two miles to burn it off. Foods high in empty calories
are easily available and are frequent selections of college
students, who may be responsible
for their food selection or preparation for the first time in their lives.
VIDEO 2
Sugar, especially from soft drinks,
and beer add calories. Learning to make healthy choices
and showing some restraint with food intake are important skills for...
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