What Is Obesity?
Obesity is an excess proportion of total body fat. A person is considered obese when his or her weight is 20% or more above normal weight. The most common measure of obesity is the body mass index or BMI. A person is considered overweight if his or her BMI is between 25 and 29.9; a person is considered obese if his or her BMI is over 30.
When you take in more calories than you burn off, you gain weight. How you eat, how active you are, and other things affect how your body uses calories and whether you gain weight.
Description of Obesity
Often referred to as a disease, obesity is actually a sign of what may well be a spectrum of different kinds of disorders genetic or environmental. In fact, there is no single definition of obesity. It may be simply an extreme degree of overweight - but a person can be overweight without being obese. A 250-pound, 6' linebacker, for example, may be overweight according to ordinary standards, but may actually have a below-average amount of body fat. In contrast, a person in a normal weight range but with very sedentary habits, could have a small muscle mass, be storing excess fat, and thus be classifiable as obese.
About one-half of all Americans are above their ideal weight, as determined by standard tables, and for the majority of them, the excess weight is in the form of body fat, not muscle mass. Of this group, half exceed their ideal weight by 20 percent or more. Hence, they are classified as obese.
Obesity has become epidemic in the U.S. and other developed countries. More than 58 million Americans are overweight, and that includes at least 1 in 5 children.
Two principal risk factors that lead to obesity, poor nutrition and lack of physical activity combined, are the second leading cause of preventable death (tobacco is first). Obesity is associated with significant increases in risk for type II diabetes mellitus, hyperlipidemia, high cholesterol, coronary artery disease, degenerative joint disease and psychosocial disability. Certain cancers - colon, rectum and prostate in men; uterus, biliary tract, breast and ovary in women - are more prevalent in the obese.