Endogenous fat oxidation during medium chain versus long chain triglyceride feeding in healthy women

Int J Obes Relat Metab Disord. 2000 Sep;24(9):1158-66. doi: 10.1038/sj.ijo.0801350.


Objective: To compare the effect of medium chain triglycerides (MCT) vs long chain triglycerides (LCT) feeding on exogenous and endogenous oxidation of long chain saturated fatty acids (LCSFA) in women.

Subjects: Twelve healthy female subjects (age 19-26 y, body mass index (BMI) 17.5-28.6 kg/m2)

Design and measurements: In a randomized cross-over design, subjects were fed weight maintenance diets providing 15%, 45% and 40% of energy as protein, carbohydrate and fat, respectively, with 80% of this fat comprising either a combination of butter and coconut oil (MCT) or beef tallow (LCT). Following 6 days of feeding, subjects were given daily oral doses of 1-(13)C labelled-myristic, -palmitic and -stearic acids for 8 days. Expired 13CO2 was used as an index of LCSFA oxidation with CO2 production assessed by respiratory gas exchange.

Results: No difference in exogenous LCSFA oxidation was observed as a function of diet on day 7. On day 14, greater combined cumulative fractional LCSFA oxidation (16.9 +/- 2.5%/5.5 h vs 9.1 +/- 1.2%/5.5 h, P < 0.007), net LCSFA oxidation (2956 +/- 413 mg/5.5 h vs 1669 +/- 224 mg/5.5 h, P < 0.01), and percentage dietary LCSFA contribution to total fat oxidation (16.3 +/- 2.3%/5.5 h vs 9.5 +/- 1.5%/5.5 h; P < 0.01) were observed in women fed the MCT vs LCT diet. With the MCT diet, but not the LCT diet, combined cumulative fractional LCSFA oxidation (P < 0.03), net LCSFA oxidation (P < 0.03), and percentage dietary LCSFA contribution to total fat oxidation (P < 0.02) were increased at day 14 as compared to day 7. Day 14 results indicated increased endogenous LCSFA oxidation during MCT feeding.

Conclusion: The capacity of MCT to increase endogenous oxidation of LCSFA suggests a role for MCT in body weight control over the long term.

Publication types

  • Clinical Trial
  • Comparative Study
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Breath Tests
  • Carbon Isotopes
  • Cross-Over Studies
  • Dietary Fats / administration & dosage*
  • Fatty Acids / metabolism*
  • Female
  • Humans
  • Myristic Acid / metabolism
  • Oxidation-Reduction
  • Palmitic Acid / metabolism
  • Pulmonary Gas Exchange
  • Stearic Acids / metabolism
  • Triglycerides / administration & dosage*
  • Triglycerides / chemistry*


  • Carbon Isotopes
  • Dietary Fats
  • Fatty Acids
  • Stearic Acids
  • Triglycerides
  • Myristic Acid
  • Palmitic Acid