Abstract/Summary

The present study examined whether the combination of medium-chain triglycerides (MCT) along with exercise suppress energy intake to a greater extent than either intervention alone. Twelve participants consumed a porridge breakfast containing 165 kcal 692.9 kJ of either vegetable or MCT oil on two separate occasions; one followed by rest for 240 min, one followed by rest broken up with 1h of cycling at 65% VO2peak starting at 120 min. At 240 min, participants consumed a buffet lunch to satiation, and recorded their food intake for the rest of the day. Expired air samples (for calculation of energy expenditure (EE)) and subjective ratings of appetite on visual analogue scales were taken every 30 min, and gastric emptying (GE) breath samples were taken every 15 min. There was no effect of either breakfast or exercise condition on energy intake at any time point (P>0.05) or any effect on subjective appetite ratings (P>0.05). Exercise trials resulted in significantly higher EE than resting trials (2960.6 kJ, 95% CI [2528.9, 3392.2]; P<0.001), and MCT increased resting EE over 4h compared to long-chain triglycerides (LCT) (124.8 kJ, 95% CI [13.5, 236.0]; P=0.031). GE was accelerated by exercise, regardless of breakfast, but delayed by MCT in both resting and exercise trials. The results show that exercise causes energy deficits via increased EE without promoting dietary compensation. MCT has no effect on energy intake or satiety, but increases EE under resting conditions. There is no additive effect of MCT and exercise on EE, intake, or appetite ratings.