The role of exercise in modulating the impact of an ultralow-fat diet on serum lipids and apolipoproteins in patients with or at risk for coronary artery disease

Background Ultralow-fat diets are known to reduce high-density lipoprotein cholesterol (HDL-C) levels. In the setting of a multicomponent lifestyle intervention program, relationships between exercise variables and HDL-C levels were examined to determine whether exercise moderates this dietary effect on serum lipids and apolipoproteins. Methods We performed a 3-month, prospective, nonrandomized lifestyle intervention study (≤10% dietary fat; aerobic exercise [180 min/wk], group support, and yoga [60 min/day]) in 120 subjects with or at risk for coronary artery disease. Results After 3 months, dietary fat intake was reduced to 8.7% ± 2.6% of total intake and the median weekly exercise time was 194 minutes. High-density lipoprotein cholesterol levels decreased by 8.3 ± 11.3 mg/dL (P < .001), and triglyceride levels increased by 17.6 ± 102.7 mg/dL (P = .026). A small dense low-density lipoprotein cholesterol (LDL-C) phenotype emerged indicated by a 13.8% LDL-C reduction accompanied by only a 2.3% reduction in apolipoprotein B levels (P = .064). Among subjects with exercise amounts less than those of the group median, HDL-C reductions were greater in those with more than (−13.5 ± 16.0 mg/dL) versus less than (−2.5 ± 7.5 mg/dL) the median reductions in fat intake (P = .026). Even among subjects who exercised >194 min/wk, HDL-C was reduced compared with baseline (−7.4 ± 7.9 mg/dL, P < .001). Conclusions An ultralow-fat diet as a component of a comprehensive lifestyle intervention induces reductions in HDL-C and the emergence of a dyslipidemic lipid profile. Aerobic exercise only partially mitigates this effect.