Overfeeding with medium-chain triglyceride diet results in diminished deposition of fat.
Level 5 - mechanism / opinion, no new human data
Animal experimental study in rats.
PubMed 6849272 · doi:10.1093/ajcn/37.1.1
What was done
Rats were overfed isocaloric diets containing either medium-chain triglycerides (MCT, 45% of total calories) or long-chain triglycerides (LCT) as the primary fat source for 6 weeks, delivered twice daily via a gastrostomy tube. Researchers evaluated body weight gain, fat depot weights, adipocyte size, carcass protein and water content, serum insulin levels, and physical activity.
What was found
MCT-fed rats gained 20% less weight (P < 0.001) and possessed fat depots weighing 23% less (P < 0.001) than isocalorically overfed LCT rats. Mean adipocyte size was also significantly smaller in the MCT group (P < 0.005). Carcass protein mass, carcass water, serum insulin concentrations, and physical activity levels did not differ between the two groups.
Why it matters
This animal study demonstrates that dietary fat composition can alter fat deposition independently of total caloric intake, supporting the hypothesis that rapid portal delivery and hepatic oxidation of MCTs limit their availability for storage in adipose tissue.
Limits
The study was performed in rats using invasive tube overfeeding, which does not replicate normal human eating behavior, digestion, or metabolism. The abstract does not report the sample size (n), baseline or absolute weight measurements, or direct measurements of energy expenditure.
Cited by
- supports Medium-chain triglycerides travel directly to the liver and are metabolized and burned off more readily than long-chain triglycerides.