Exercise prevents the accumulation of triglyceride-rich lipoproteins and their remnants seen when changing to a high-carbohydrate diet

We tested the hypothesis that daily aerobic exercise opposes the fasting hy pertriglyceridemia and exaggerated postprandial lipemia observed after subs tituting dietary fat with carbohydrate. Eight healthy postmenopausal women aged 51 to 66 years consumed the same high-fat mixed meal on 3 occasions: ( 1) after 3 days on a low-carbohydrate diet (35%, 50%, and 15% energy from c arbohydrate, fat, and protein, respectively); (2) after 3 days on an isoene rgetic high-carbohydrate diet (corresponding values 70%, 15%, and 15%); and (3) after 3 days on the. same high-carbohydrate diet with 60 minutes of br isk walking daily. Plasma triglycerides were higher after the high-carbohyd rate diet than after the low-carbohydrate diet: fasting, 1.58+/-0.19 versus 0.96+/-0.12 mmol/L, respectively; 6-hour postprandial area under concentra tion versus time curve, 13.74+/-1.57 versus 10.12+/-1.15 (mmol/L)Xhour, res pectively (both P<0.01). In the fasted and postprandial states, concentrati ons of apolipoproteins B-48 and B-100 in the triglyceride-rich lipoprotein fraction were significantly higher after the high-carbohydrate diet, as was the concentration of remnant-like lipoprotein particle cholesterol (a meas ure of lipoprotein remnants). These carbohydrate-induced increases in the n umber of circulating triglyceride-rich particles and their remnants were ab olished when subjects had exercised daily during the high-carbohydrate diet .