Chapter 18 is dedicated to nutrition and it uses easy-to-understand graphics and tables to show the important role nutrition has in a maintaining a healthy life.

Overweight and obesity are major risk factors for pre-diabetes and type 2 diabetes. Poor diet and physical inactivity, resulting in an energy imbalance (more calories consumed than expended), are the most important factors contributing overweight and obesity.

Good nutrition is vital to good health and it is essential for the healthy growth and development of children and adolescents. Major causes of morbidity and mortality in the United States are related to poor diet and a sedentary (inactive) lifestyles. Specific diseases and conditions associated with poor diet include cardiovascular disease (CVD), hypertension, dyslipidemia (abnormal blood fats), type 2 diabetes, overweight and obesity, osteoporosis, constipation, diverticular disease, iron deficiency anemia, oral disease, malnutrition, and some cancers. Lack of physical activity has been associated with cardiovascular disease, hypertension, overweight and obesity, osteoporosis, diabetes, and certain cancers. Furthermore, muscle strengthening and improving balance can reduce falls and increase functional status among older adults. Together with physical activity, a high quality diet that does not provide excess calories should enhance the health of most individuals.