ABSTRACT
At least 17 genes have been associated with common forms of obesity, and 18 have been • associated with type 2 diabetes. Positive energy balance is the essential ingredient required to store body fat and become • overweight and obese. The concept of energy balance does not tell us all that is important: genetic factors, gender • differences in fat distribution, or effects of age or medications. An epidemiological model of obesity describes the environmental factors such as maternal • fatness, sleep time, viruses, toxins, and drugs as contributing mechanisms. Cost of food plays an important role in food choices.• A homeostatic model for control of food intake and energy expenditure helps isolate the • specic mechanisms that can be targeted for understanding and treating the problem.
