Medium Chain Triglycerides (MCTs) are a type of fat that has had a lot of positive press recently. Most of the fats and oils commonly found in food, including most animal and vegetable fats, are long chain triglycerides (LCTs). MCTs are rare in the normal diet, but coconut and palm oils are very rich sources.
MCTs differ from LCTs by the number of carbon atoms in their fatty acid chains. MCTs generally have between six and twelve carbon atoms in each chain, while anything above that falls into LCT territory.
This gives MCTs properties that LCTs don't have, including some beneficial effects on weight loss MCTs have been shown to enhance thermogenesis, and MCT consumption has been shown to reduce food intake compared to LCT. The mechanism of the latter effect is not known.
A group of researchers set out to change this, and decided to investigate the possibility that MCT caused hormonal changes that affect the appetite, that LCT consumption does not induce. A small group of overweight men participated in two blind crossover studies which compared the relative effects of MCT and LCT. In the first study, the men consumed 20g of either MCT or LCT with their breakfast, and food consumption was measured at lunch, three hours later. In the second, the men received 10g of MCT or LCT one hour before lunch, and food intake was once again measured. Blood was taken to look at the levels of hormones and metabolites, throughout the experiment.
This set of studies showed some strong results. As we have seen before, preloading with MCT prior to mealtime had a very significant effect on reducing food intake. Levels of metabolites measured before the meal showed that people who had consumed MCT displayed a reduced elevation in blood triglyceride and glucose levels compared to the LCT group. They also showed some significant changes in the hormone levels, with a greater increase in levels of peptide YY, known in various circumstances as both an appetite reducer and stimulator, and leptin, sometimes known as the satiety hormone, in consumers of MCT. This seems to correlate with the observed effects of MCT intake. On the other hand, the scientists reported that the correlations between insulin levels, levels of a hormone called Glucagon-like peptide-1 (GLP-1), which stimulates insulin release and contributes to feelings of satiety, and overall concentrations of peptide YY were opposite to expectations.
Although this research demonstrated very clearly that MCT consumption is an excellent way to reduce total food intake, it does not point to any clear hormonal mechanism for this effect.
Thankfully, what we do know is that using MCT is a natural, safe, and effective way to control the appetite. It is easy to replace dietary fats and oils with delicious and MCT-rich alternatives. This could be the small change that kickstarts your weight loss.
St-Onge MP, Mayrsohn B, O'Keeffe M, Kissileff HR, Choudhury A, Laferrère B. Impact of medium and long chain triglycerides consumption on appetite and food intake in overweight men. Eur J Clin Nutr. 2014 Jul 30.