Thermic effect of medium-chain and long-chain triglycerides in man.
Level 3 - non-randomized controlled study
Small controlled crossover trial in 7 participants; randomization not stated in abstract
PubMed 3532757 · doi:10.1093/ajcn/44.5.630
What was done
Indirect calorimetry was used to measure metabolic rate before and for 6 hours after 400 kcal test meals containing either medium-chain triglycerides (MCT) or long-chain triglycerides (LCT) in seven healthy men. Blood measurements included plasma beta-hydroxybutyrate, serum insulin, and plasma triglycerides.
What was found
Mean postprandial oxygen consumption rose 12% above basal levels after the MCT meal versus 4% after the LCT meal. Ingestion of MCT caused a 25-fold increase in plasma beta-hydroxybutyrate and a slight increase in serum insulin, neither of which occurred after LCT. Plasma triglycerides rose 68% following the LCT meal but showed no change following the MCT meal.
Why it matters
This study provides mechanistic evidence that MCTs elicit higher acute diet-induced thermogenesis and ketogenesis than standard long-chain dietary fats in humans.
Limits
The sample size is extremely small (n = 7) and limited to healthy males. The abstract does not specify whether meal administration was randomized. The trial measured only acute metabolic responses over a single 6-hour postprandial period, leaving long-term impacts on total energy balance and body weight unmeasured.