Whether a person is pudgy or lean depends on a complex interplay of personal habits and favorite foods, genetics and psychology, life stresses and social circumstances. At one level, the cause of weight gain is elementary. But there are many ways to be out of balance. So right there you have two different causes of obesity. And the list goes on.
Some people eat a lot to cope with stress.
Other overeaters just don't notice the calories coming in. Still others are subject to the luck of the genetic draw. A 1992 study showed that obese people underreport the amount of food they eat and overestimate the calories they burn through exercise. Dr. Margo Denke of the University of Texas Southwestern Medical Center at Dallas is a weight-loss specialist. Her approach is to ask people when in their lives they gained weight, what they eat on a typical weekday and on the weekends, and whether they take advantage of opportunities to be active.