A reduction in dietary saturated fat decreases body fat content in overweight, hypercholesterolemic males

Abstract

Background and Aim: The effect of the quality of dietary fat on body composition is unknown. Our objective was to determine whether body composition is modified by the isocaloric substitution of a diet rich in saturated fat by a diet high in monounsaturated fat (Mediterranean diet) or a carbohydraterich diet in overweight subjects with hypercholesterolemia. Methods and Results: The study involved 34 hypercholesterolemic males aged 18–63 years with a body mass index (BMI) of 28.2 (2.6), all of whom consumed a diet rich in saturated fat (SAT) for 28 days. They were then randomly divided into two groups of 17 subjects and underwent two dietary periods of 28 days each in a crossover design: a Mediterranean diet high in monounsaturated fat (MONO) and a carbohydrate-rich diet (CHO). The order of the diets was different for the two group. The CHO diet contained 57% CHO and 28% total fat (<10% saturated fat, 12% monounsaturated fat and 6% polyunsaturated fat); the Mediterranean diet contained 47% CHO and 38% fat (<10% saturated fat, 22% monounsaturated fat −75% of which was provided by olive oil- and 6% polyunsaturated fat). The variables measured at the end of each dietary intervention period were: 1) body composition by means of bioelectrical impedance; 2) plasma lipoproteins using enzymatic techniques; and 3) fatty acids in cholesterol esters by means of gas chromatography. BMI and the waist/hip ratio remained the same during the three dietary periods. A decrease in fat was observed when changing from a saturated fat diet (23.3 (6.3) kg) to a Mediterranean diet (20.8 (7.2) kg) ( p<0.05), or a carbohydrate-rich diet (20.6 (6.7) kg) ( p<0.05). Lean mass increased when changing from a SAT diet (58.4 (7.0) kg) to a CHO diet (60.2 (7.0) kg) ( p<0.05). Conclusion: The isocaloric substitution of a saturated fatrich diet by a Mediterranean or carbohydrate-rich diet decreases total body fat in hypercholesterolemic males.