OBESITY: II. ETIOLOGICAL ASPECTS

Abstract

Obesity is invariably the result of an overall intake of energy which has exceeded the total dissipation of energy by the body, i.e., a positive energy balance. With the few exceptions associated with an abnormally low basal metabolic rate (not limited to fat people), the mechanisms for the dissipation of energy from the obese body are normal. The fundamental fault, therefore, is in the cause or causes of an excessive desire for food. Among the exptl. mechanisms leading to a desire for excessive amounts of food are bilateral hypothalamic injury, severe and prolonged insulin hypoglycemia and hereditary bulimia in a strain of mice; these may not be significant causal factors in human obesity. Abnormalities of the endocrine system affecting adipose tissue are more importantly related to the distribution of body fat than to its excessive accumulation. The search for metabolic aberrations leading to obesity has not been fruitful. Various environmental influences upon appetite are established causes of obesity. The classification of obesity as exogenous, endogenous, endocrine, pituitary, thyrogenous, gonadal, etc., is misleading and should be discontinued.