Backgroud  Hypertriglyceridaemia, a consistent feature of dyslipidaemia in the metabolic syndrome (MetS), is related to the extent of abdominal fat mass and altered adipocytokine secretion. We determined the effect of weight loss by dietary restriction on markers of triglyceride‐rich lipoprotein (TRL) metabolism and plasma adipocytokines.

Design  Thirty‐five men with MetS participated in a 16 week randomized controlled dietary intervention study. Apolipoprotein (apo) C‐III, apoB‐48, remnant‐like particle (RLP)‐cholesterol, total adiponectin, high‐molecular weight (HMW) adiponectin, and retinol‐binding protein‐4 (RBP‐4) concentrations were measured using immunoassays.

Results  Compared with weight maintenance (n = 15), weight loss (n = 20) significantly decreased body weight, plasma insulin, triglycerides, total cholesterol, low‐density lipoprotein (LDL)‐cholesterol and lathosterol (P < 0·05). Weight loss also decreased plasma concentrations of apoC‐III (–33%), apoB‐48 (–37%), very low‐density lipoprotein (VLDL)‐apoB (–43%), RLP‐cholesterol (–48%), and RBP‐4 (–20%), and significantly increased plasma total (+20%) and HMW‐adiponectin (+19%) concentrations. In the weight loss group, reduction in plasma apoC‐III was associated (P < 0·05) with reduction in plasma apoB‐48, VLDL‐apoB, RLP‐cholesterol and triglycerides. Increase in total adiponectin was associated (P < 0·05) with the reduction in plasma VLDL‐apoB and triglycerides. The changes in HMW‐adiponectin and RBP‐4 were not associated with changes in plasma apoB‐48, apoC‐III, VLDL‐apoB, RLP‐cholesterol or triglycerides. In multiple regression analysis including changes in visceral fat, insulin and total adiponectin concentrations, the fall in plasma apoC‐III concentration was an independent predictor of the reductions in plasma apoB‐48, VLDL‐apoB, RLP‐cholesterol and triglycerides concentrations.

Conclusions  In men with MetS, weight loss decreases the plasma concentrations of apoB‐48, VLDL‐apoB, RLP‐cholesterol and triglycerides. This effect could partly relate to concomitant changes in plasma apoC‐III and adiponectin concentrations that accelerate the catabolism of TRLs.