Abdominal obesity.

The application of magnetic resonance imaging and computed tomography to obesity research has changed the focus from body mass and skinfold thickness to abdominal fat mass and visceral adiposity. Intra-abdominal fat constitutes less than 20% of total body fat but is a major determinant of fasting and postprandial lipid availability because of its physiological (lipolytic rate and insulin resistance) and anatomical (portal drainage) properties. High levels of serum free fatty acids, as a result of abdominal obesity, cause excessive tissue lipid accumulation and contribute to dyslipidaemia, beta cell dysfunction, and hepatic and peripheral insulin resistance. An individual's risk of non-insulin dependent diabetes mellitus and cardiovascular disease relates closely to the inheritance of central obesity and susceptibility to tissue lipotoxicity.