Effect of weight loss with reduction of intra-abdominal fat on lipid metabolism in older men

How weight loss improves lipid levels is poorly understood. Cross-sectional studies have suggested that accumulation of fat in intraabdominal stores ( IAF) may lead to abnormal lipid levels, increased hepatic lipase (HL) activ ity, and smaller low density lipoprotein (LDL) particle size. To determine what effect loss of IAF would have on lipid parameters, 21 healthy older me n underwent diet-induced weight loss. During a period of weight stability b efore and after weight loss, subjects underwent studies of body composition , lipids, measurement of postheparin lipoprotein and HL lipase activities, cholesteryl ester transfer protein activity, and insulin sensitivity (Si). After an average weight loss of 10%, reductions in fat mass, IAF, and abdom inal sc fat were seen, accompanied by reductions in levels of triglyceride, very low density lipoprotein cholesterol, apolipoprotein B, and HL activit y. High density lipoprotein-2 cholesterol and Si increased. In those subjec ts with pattern B LDL at baseline, LDL particle size increased. Cholesteryl ester transfer protein activity did not change. Changes in IAF and Si corr elated with a decrease in HL activity (although not independently of each o ther). In summary, in men undergoing diet-induced weight loss, only loss of LAF was found to be associated with a reduction in HL, which is associated with beneficial effects on lipid levels.