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Chapter 3 Nutrition 81
hen you eat nutritious foods today, you lower your risk of de-
veloping diseases later in life. People who follow a healthy eat-
ing plan and maintain a healthy body weight are less likely to
develop serious illnesses such as heart disease, high blood pressure, diabe-
tes, stroke, and cancer. Eating a nutritious diet also prevents health prob-
lems such as obesity, cavities, iron defi ciency, and osteoporosis.
Overall, the body needs about 45 different nutrients per day. This is
why eating a varied diet full of nutritious foods is important for maintain-
ing good health.
A healthy eating plan includes foods that supply the amounts and
types of nutrients your body needs to be healthy. In this section, you will
learn how to make smart food choices and how to create a balanced diet.
You will also learn about the hazards of poor nutrition.
Dietary Guidelines
The United States Departments of Agriculture (USDA) and Health and
Human Services (HHS) publish the Dietary Guidelines for Americans, which
is revised every fi ve years. The Dietary Guidelines provide recommenda-
tions for establishing eating patterns to promote health. The guidelines
promote two key concepts:
• Maintain calorie balance over time to achieve and sustain a
healthy weight.
• Focus on consuming nutrient-dense foods and beverages.
Maintain Calorie Balance
As you learned earlier in this chapter, nutrients provide the body with
the energy it needs to function. The energy provided by food is measured
in terms of a unit called a calorie. Foods that provide larger amounts of
energy are higher in calories than foods that provide smaller amounts of
energy.
Some types of nutrients provide more calories than others (Figure 3.9
on the next page). Carbohydrates and protein each provide 4 calories per
gram. Fats provide 9 calories per gram, more than any other source.
Your calorie balance in a given day is determined by two distinct
factors:
• the number of calories you consume through eating and drinking
(this is energy in to your body)
• the number of calories you burn through the work of your
metabolism and your daily physical activities (this is energy out of
your body)
Your body burns calories to perform the many functions of your
metabolism that keep you alive, such as eating, sleeping, and breathing.
You also burn calories in the course of daily life—while walking to class,
lifting a heavy backpack, and cleaning your room.
W
calorie
a unit of measurement for
energy provided by food
metabolism
the rate at which the body
uses energy