Journal of the Academy of Nutrition and Dietetics
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Review Meta Analysis Comparative Study
Comparison of effects of long-term low-fat vs high-fat diets on blood lipid levels in overweight or obese patients: a systematic review and meta-analysis.
Dietary fat plays an important role in the primary prevention of cardiovascular disease, but long-term (≥12 months) effects of different percentages of fat in the diet on blood lipid levels remain to be established. Our systematic review and meta-analysis focused on randomized controlled trials assessing the long-term effects of low-fat diets compared with diets with high amounts of fat on blood lipid levels. Relevant randomized controlled trials were identified searching MEDLINE, EMBASE, and the Cochrane Trial Register until March 2013. ⋯ Meta-regression revealed that lower total cholesterol level was associated with lower intakes of saturated fat and higher intakes of polyunsaturated fat, and increases in HDL cholesterol levels were related to higher amounts of total fat largely derived from monounsaturated fat (of either plant or animal origin) in high-fat diets (composition of which was ~17% of total energy content in the form of monounsaturated fatty acids, ~8% of total energy content in the form of polyunsaturated fatty acids), whereas increases in triglyceride levels were associated with higher intakes of carbohydrates. In addition, lower LDL cholesterol level was marginally associated with lower saturated fat intake. The results of our meta-analysis do not allow for an unequivocal recommendation of either low-fat or high-fat diets in the primary prevention of cardiovascular disease.