in a satisfying diet. Nearly all Americans need
to be more active, because a sedentary
lifestyle is unhealthful. Increasing the calories
spent in daily activities helps to maintain
health and allows people to eat a nutritious
and enjoyable diet.
What is a healthful diet?
Healthful diets contain the amounts of
essential nutrients and calories needed to
prevent nutritional deficiencies and excesses.
Healthful diets also provide the right balance
of carbohydrate, fat, and protein to reduce
risks for chronic diseases, and are a part of a
full and productive lifestyle. Such diets are
obtained from a variety of foods that are
available, affordable, and enjoyable.
The Recommended Dietary Allowances
refer to nutrients
Recommended Dietary Allowances (RDAs)
represent the amounts of nutrients that are
adequate to meet the needs of most healthy
people. Although people with average nutri-
ent requirements likely eat adequately at
levels below the RDAs, diets that meet RDAs
are almost certain to ensure intake of enough
essential nutrients by most healthy people.
The Dietary Guidelines describe food choices
that will help you meet these recommenda-
tions. Like the RDAs, the Dietary Guidelines
apply to diets consumed over several days
and not to single meals or foods.
The Dietary Guidelines describe food choices
that promote good health
The Dietary Guidelines are designed to help
Americans choose diets that will meet nutri-
ent requirements, promote health, support
active lives, and reduce chronic disease risks.
Research has shown that certain diets raise
risks for chronic diseases. Such diets are high
in fat, saturated fat, cholesterol, and salt and
they contain more calories than the body
3
reduce the risk for chronic diseases, such as
heart disease, certain cancers, diabetes,
stroke, and osteoporosis, that are leading
causes of death and disability among
Americans. Good diets can reduce major risk
factors for chronic diseases
—
factors such as
obesity, high blood pressure, and high blood
cholesterol.
Foods contain energy, nutrients, and other
components that affect health
People require energy and certain other
essential nutrients. These nutrients are
essential because the body cannot make
them and must obtain them from food.
Essential nutrients include vitamins, minerals,
certain amino acids, and certain fatty acids.
Foods also contain other components such
as fiber that are important for health.
Although each of these food components has
a specific function in the body, all of them
together are required for overall health.
People need calcium to build and maintain
strong bones, for example, but many other
nutrients also are involved.
The carbohydrates, fats, and proteins in
food supply energy, which is measured in
calories. Carbohydrates and proteins provide
about 4 calories per gram. Fat contributes
more than twice as much
—
about 9 calories
per gram. Alcohol, although not a nutrient,
also supplies energy
—
about 7 calories per
gram. Foods that are high in fat are also high
in calories. However, many lowfat or nonfat
foods can also be high in calories.
Physical activity fosters a healthful diet
Calorie needs vary by age and level of activ-
ity. Many older adults need less food, in part
due to decreased activity, relative to younger,
more active individuals. People who are
trying to lose weight and eating little food
may need to select more nutrient-dense
foods in order to meet their nutrient needs
2