Adipose tissue of morbidly obese patients: clinical implications of distribution, morphology, and metabolism.

As a consequence of their increased total adipose tissue mass, morbidly obese patients have many more fat cells than individuals of normal weight and the cells are enlarged compared to normal. Contrary to earlier beliefs, fat cell numbers can increase throughout adult life. Once formed, fat cells do not undergo involution. Thus, it seems that an individual who has reached the morbidly obese state maintains an increased amount of body fat that limits his/her ability to achieve and maintain commonly accepted levels of "ideal" body weight. Recently the distribution of adipose tissue has been shown to be an important predictor of obesity-associated morbidity and mortality in large population studies. A "male" or central distribution of fat is a significant risk factor for the development of diabetes, hyperlipidemia, hypertension, and coronary heart disease. Sex- and site-specific variations in the distribution of adipose tissue cell size and metabolic activity have been demonstrated that may be of etiologic importance for the development of serious comorbid conditions in obesity.