Remnant lipoprotein metabolism is improved more when body weight is reduced by exercise than by dietary restriction

BACKGROUND: Remnant lipoprotein levels during weight-loss programs have not been examined in detail. We investigated the effects of reducing body weight by exercise and by dietary restriction on lipid metabolism including remnant-like particle-cholesterol (RLP-C) and apolipoprotein B48 (apo B48). METHODS: Six adult male volunteers participated in 2 experiments over 10 days. The first 5 days were an adjustment period (energy intake, 2656+/-150 kcal/day; mean+/-SEM). During the second 5 days, the participants either exercised on a bicycle ergometer to consume 886+/-50 kcal/day or reduced their energy intake to 1770+/-100 kcal/day. RESULTS: Serum triglyceride (TG) and RLP-C levels were significantly lower, whereas the increase in high density lipoprotein-cholesterol (HDL-C) level was significantly larger after exercise than after dietary restriction. We measured changes (Delta) in serum levels and identified positive correlations between Delta insulin and Delta TG, Delta apo B48 (p<0.05) and Delta RLP-C (p=0.050) only during exercise. CONCLUSIONS: Reducing body weight by exercise has more beneficial effects on lipid metabolism than a dietary approach, and improved insulin resistance accompanies the decrease of serum remnant lipoprotein levels.