Very-low-fat diets may be associated with increased risk of metabolic syndrome in the adult population

Background & aims Although fat intake has often been targeted to decrease the prevalence of metabolic syndrome; however decreasing dietary fat intake has not had this result. We studied the association between fat intake and the prevalence of metabolic syndrome in adults using KNHANES 2007–2013 data, a representative sample of the non-institutionalized civilian population. Methods This cross-sectional study included 34,003 Korean adults aged ≥19 years. Adjusted odds ratios (OR) for the components of metabolic syndrome were measured according to fat intake (≤15, 15–25, ≥25% of daily energy intake) while controlling for covariates that affect metabolic syndrome using linear and logistic regression analysis while incorporating the sample weights for the complex sample design of the survey. Results Surprisingly, the prevalence of metabolic syndrome was significantly higher in the ≤15% fat intake group (OR = 1.277), accompanied by lower daily energy intake compared to the reference group (≥25% fat intake). Higher daily fat intake was associated with significantly lower ORs for four components of metabolic syndrome, except diabetes mellitus, using continuous variable analysis, whereas only three serum components (serum HDL, serum triglyceride, and blood pressure) exhibited significantly higher ORs in the lowest tertile of dietary fat intake (≤15%) compared with the reference group (≥25% fat-intake tertile). Subjects in a low-fat intake group had about 6.0 g polyunsaturated fatty acid/day that did not meet the recommended intake. Consumption of grain groups was a significant predictor of low fat intake, whereas milk food groups were significant predictors of not having low fat intake. Subjects in the low-fat group (≤15%) had much lower daily energy intake, by 500 kcal, compared with subjects who consumed high-fat diets (≥25%). All nutrients except carbohydrates had significantly lower mean values in the low-fat-intake group as compared to the high-fat-intake group. Conclusions Low fat intake, <15%, was associated with a higher incidence of metabolic syndrome in the adult population, despite the daily energy intakes being lower by 500 kcal and the intakes with proper ratio (1:1.03:1.01) of saturate, monounsaturated and polyunsaturated fatty acid; this may be related to lower intake of various nutrients other than carbohydrates.