Diacylglycerols affect substrate oxidation and appetite in humans

Meals rich in diacylglycerols (DGs) instead of triacylglycerols (TGs) show beneficial effects on lipid metabolism and energy balance. These effects are probably attributable to differences in DG and TG metabolism, especially postprandial fat oxidation. We assessed the effects of partial replacement of TGs with DGs on substrate oxidation, energy expenditure (EE), relevant blood variables, and appetite. Twelve healthy, dietarily unrestrained women participated in a single-blind, placebo-controlled, randomized trial with crossover design. For 3 d before and throughout a 36-h stay in a respiration chamber, subjects were fed energy-maintenance amounts of a diet consisting of 55% of energy from carbohydrate, 15% from protein, and 30% from fat. In the respiration chamber, 40% of the fat was consumed as DG-rich (80% DGs) oil or as TG-based control oil with a similar fatty acid profile. Fat oxidation was significantly higher with DG treatment than with TG treatment. Appetite profiles during day 1 (24 h) did not differ significantly between the DG and TG treatments; however, feelings of hunger, appetite, estimated prospective food intake, and desire to eat were all significantly lower on day 2 (12 h) with DG treatment. Mean plasma beta-hydroxybutyrate tended to be higher with DG treatment, and the difference between the 2 treatments was significant at 1130 on day 2. Plasma lipid concentrations and resting and 24-h EE did not differ significantly between the 2 treatments. Consumption of DGs in place of TGs does not alter EE but produces metabolic effects, particularly increases in fat oxidation, which may be associated with improved appetite control and energy balance.