Effects of diet- and exercise-induced weight loss on visceral adipose tissue in men and women.

The effects of diet- and exercise-induced weight loss on visceral adipose tissue (VAT) distribution in both men and women have been reviewed. In general, current knowledge is based on studies that have assessed the influence of diet alone on VAT in obese women. For every kilogram of diet-induced weight loss, the corresponding reduction in VAT expressed in absolute terms is approximately 3 to 4 cm2, and in relative terms is approximately 2 to 3%. Thus, a diet-induced weight loss of approximately 12 kg corresponds to a 30 to 35% reduction in VAT. Two studies that consider the effects of exercise per se on VAT report conflicting results. There appears to be a resistance to VAT reduction in obese women, whereas exercise-induced weight loss is associated with significant reductions in VAT in men. It was also reported that in obese men, reductions in VAT induced by the combination of diet and exercise are not different from those observed in response to diet alone. It is unclear whether the results of these studies reflect a biological truth or are confounded by methodological problems associated with the control of energy intake and expenditure in free-living patients. Evidence suggests that changes in waist circumference and sagittal diameter are well correlated with corresponding changes in VAT. A 1 cm reduction in waist circumference corresponds to a 5 cm2 (4%) reduction in VAT area at the L3 level. Data on the separate effects of diet- and exercise-induced weight loss on VAT from well controlled studies are required to advance current knowledge with respect to the effects of diet and exercise on the adipose tissue depot that conveys the greatest health risk.