Obesity Introduction One in three or 58 million American adults aged 20 through 74 are overweight. By a similar definition, more than one in five children and adolescents aged 6 through 17 are also overweight. Overweight and obesity is a known risk factor for diabetes, heart disease, high blood pressure, gallbladder disease, arthritis, breathing problems, and some forms of cancer. Overweight is the excess amount of body weight that includes muscle, bone, fat, and water.
Obesity is the excess accumulation of body fat.
However, for practical purposes, most people who are overweight are also obese. Doctors and scientists generally agree that men with more than 25 percent body fat and women with more than 30 percent body fat are obese. However, it is difficult to measure body fat precisely. The most accepted method has been to weigh a person underwater. But underwater weighing is a procedure limited to laboratories with special equipment.