Diet-induced thermogenesis and satiety in humans after full-fat and reduced-fat meals

Diet-induced thermogenesis was measured during and after a full-fat lunch, an identical but reduced-fat, reduced-energy lunch, and an iso-energetic reduced-fat lunch in 32 normal-weight men and women, age 35-55. Hunger and satiety were scored during and after the lunches, and their relationship to diet-induced thermogenesis was assessed. Diet-induced thermogenesis was relatively higher after the reduced-fat, reduced-energy lunch compared to the full-fat lunch (6.7% vs. 5.2%; p < 0.05). The respiratory quotients were significantly lower after the full-fat lunch than after the 2 reduced-fat lunches (p < 0.05). After the iso-energetic reduced-fat lunch, hunger scores were significantly reduced and satiety scores significantly increased (p < 0.05) until 1800 h. compared to the other 2 lunches. Satiety scores were positively related to the magnitude of diet-induced thermogenesis expressed as an absolute increase in metabolic rate during and after the meal. We conclude that hunger and satiety scores, substrate utilization, and diet-induced thermogenesis showed clear and different short-term responses to diets that differed with respect to the percentage energy from fat and/or the energy content of the meal.