Acute effects of three high-fat meals with different fat saturations on energy expenditure, substrate oxidation and satiety

Abstract

To compare the acute effects of three fatty meals with different fat quality on postprandial thermogenesis, substrate oxidation and satiety. Twenty-nine healthy men aged between 18 and 30 years participated in a randomised crossover trial comparing the thermogenic effects of three isocaloric meals: high in polyunsaturated fatty acids from walnuts, high in monounsaturated fatty acids from olive oil, and high in saturated fatty acids from fat-rich dairy products. Indirect calorimetry was used to determine resting metabolic rate, respiratory quotient, 5-h postprandial energy expenditure and substrate oxidation. Satiety was estimated by using visual analogue scales and measuring caloric intake in a subsequent ad libitum meal. Five-h postprandial thermogenesis was higher by 28% after the high-polyunsaturated meal (p=0.039) and by 23% higher after the high-monounsaturated meal (p=0.035) compared with the high-saturated meal. Fat oxidation rates increased nonsignificantly after the two meals rich in unsaturated fatty acids and decreased nonsignificantly after the high-saturated fatty acid meal. Postprandial respiratory quotient, protein and carbohydrate oxidation, and satiety measures were similar among meals. Fat quality determined the thermogenic response to a fatty meal but had no clear effects on substrate oxidation or satiety.