Nutritional Disorders Chapter 5. The prevalence of obesity in the USA is high and rising higher. Among women, obesity is strongly associated with socioeconomic status, being twice as common among those with lower socioeconomic status as it is among those with higher status. But in another sense, it is elusive, involving the regulation of body weight, primarily body fat. How this regulation is achieved is not yet fully understood.
Weight is regulated with great precision.
For example, during a lifetime, the average person consumes at least 60 million kcal. Regulation of body weight is believed to occur not only in persons of normal weight but also among many obese persons, in whom obesity is attributed to an elevation in the set point around which weight is regulated. The determinants of obesity can be divided into the genetic, the environmental, and the regulatory. For example, mutations in the ob gene have led to massive obesity in mice. The existence of leptin supports the idea that body weight is regulated, because leptin serves as a signal between adipose tissue and the areas of the brain that control energy metabolism, which influences body weight.