Scientific Reports · 5 authors, 5 centres
This summary was generated by AI from a single paper. It has not been reviewed by a clinician and is not clinical advice. Verify against the source before acting on it.
This secondary analysis of a randomised trial in 24 men with overweight/obesity found that a 5-day high-fat diet significantly altered lipoprotein subfraction profiles, and that 5 days of morning or evening exercise training further modified these profiles compared to no exercise, with no clear difference between exercise times. The study is limited by its small sample size, short duration, and male-only participants, and the findings are not intended as clinical recommendations.
High levels of LDL cholesterol are a major risk factor for atherosclerotic cardiovascular disease (ASCVD), and lifestyle modifications like diet and exercise are key for prevention. This study investigated how a high-fat diet (HFD) and the timing of exercise (morning vs. evening) affect lipoprotein subfraction profiles, which may have different associations with ASCVD risk than standard lipid measures. Methods: This was a secondary analysis of a three-armed randomised trial involving 24 men with overweight/obesity. All participants consumed an HFD (65% fat, 15% carbohydrate, 20% protein) for 11 days. After 5 days, they were randomised to no exercise (CONTROL, n=8), morning exercise (EXam, n=8), or evening exercise (EXpm, n=8) for days 6-10. Exercise included high-intensity interval training and moderate-intensity cycling. Lipoprotein subfractions (100 variables) were analyzed using NMR spectroscopy in fasting and postprandial samples at baseline, after 5 days of HFD, and after the exercise intervention. Key Results: Five days of HFD induced significant changes in 31/100 fasting lipid subfraction variables (q < 0.05), including reductions in VLDL cholesterol and triglycerides in some subfractions, and increases in larger LDL particles. Exercise training (both morning and evening) induced systematic changes in lipid subfraction profiles compared to CONTROL, with little difference between EXam and EXpm. Exercise reduced concentrations of >20% of fasting lipid subfractions. Specifically, EXpm reduced fasting cholesterol in three LDL subfractions by ~30%, while EXam only reduced the largest LDL particle concentration by 19% (all q < 0.05). Exercise also affected smaller HDL particles (HDL-3 and HDL-4). Limitations: The study had a small sample size (n=8 per group), was limited to men, and had a short intervention duration (5 days of exercise). The timing of blood sampling differed between exercise groups (12 vs. 24 hours post-exercise for fasting samples), which is a limitation. The findings are from a controlled experimental setting and should not be taken as clinical recommendations. Implications: The study suggests that short-term HFD and exercise can alter lipoprotein subfraction profiles in ways that may be beneficial for cardiovascular health, but the results are preliminary and require further research in larger, more diverse populations.
