Abstract
Obesity is a leading health problem in the United States and globally. Relatively few people with obesity achieve long-term weight control, suggesting that obesity and resistance to weight change represent functional adaption of energy homeostasis to the environment. The purpose of this article is to synthesize the literature regarding the relationship between environmental temperature and body weight and fat mass to provide a new explanation of obesity as a problem of maintaining core body temperature. Chronic exposure to cool environmental temperatures likely contributed to the obesity epidemic, and passive whole-body warming may be a promising intervention for weight control.