Gene–Environment Interactions in Obesity
Obesity in modern society is reaching epidemic proportions. Once thought to be a problem restricted to developed nations, excess adiposity is becoming a more significant issue in the developing world as well. The issue has such serious implications for public health that the American Medical Association has classified obesity as a disease. Further, the rate of obesity and overweightness has skyrocketed over the past 50 years. Why have we gotten so fat? Weight gain is a balance between energy intake and expenditure. Some individuals appear to be genetically predisposed to gaining weight, while others are resistant. Environmental factors, such as access to high caloric content food, decreased physical activity, have profound modifying effects on that predisposition. This chapter is an attempt to provide a broad overview of the genetic and environmental factors that affect the development of obesity, as well as some insight into how these factors interact with one another.