Medium-Chain Triglycerides (MCTs)

There is conflicting evidence that medium-chain triglyceride (MCT) oil (triglycerides with fatty acid chains that range from 6 to 12 carbon atoms) may have certain beneficial attributes for athletes. MCT oil is directly absorbed and rapidly catabolized into fatty acids and glycerol. It is easily and quickly oxidized for energy and appears to mimic the effects of carbohydrate metabolism rather than fat metabolism. There is also some evidence that it enhances the movement of fats from storage to be burned as energy, and it may also increase the rate at which energy is burned (i.e., a higher energy metabolism).^22-25 In a study assessing the relative impact of carbohydrate versus carbohydrate plus MCT oil on cycling time-trial performance, carbohydrate improved performance on the 100-kilometer distance, but the addition of MCT oil did not further improve performance.²⁶ Another study suggests that the timing of MCT oil consumption is an important factor in endurance performance. Consumption of 400 milliliters (13.5 ounces) of a 3.44 percent MCT oil solution before the time trial, plus a 10 percent glucose solution during the time trial, was associated with improved performance over the time-trial distance.²⁷ It was concluded that a reduced reliance on glycogen and an enhanced reliance on fat (MCT oil) was responsible for this observed performance enhancement. By contrast, a study of regular MCT oil consumption neither improved endurance nor altered energy metabolism in well-trained male runners.²⁸ In addition, there is some evidence that MCT oil supplementation may adversely alter the blood lipid concentrations, which should be seriously considered in athletes with family histories of heart disease.²⁹

MCT oil consumption may offer an advantage for athletes having difficulty sustaining a desirable body composition. Healthy people who consume 5 to 10 grams (45 to 90 calories) of MCT oil experience a greater diet-induced thermogenesis than after the equivalent consumption of long-chain triglycerides (the most common form of fat found in foods), and this higher thermogenesis may stimulate weight loss.^30,31

Although it does not exist in concentrated amounts in any food, MCT oil is available in many stores, and because it is saturated, it is stable and has a long shelf life. For athletes who find it difficult to consume sufficient total energy, consumption of 2 to 3 tablespoons (30 to 45 milliliters) of MCT oil may prove to be beneficial. MCT oil is burned differently than other fats, so taking this small amount may be a good way to ensure that athletes who have difficulty taking in enough calories can meet their needs.

Please note that the maximum consumption of MCT oil for most athletes should not exceed 30 grams (270 calories). Exceeding this amount dramatically increases the risk of developing GI distress, including diarrhea.³² MCT oil has, therefore, some inherent limitations in contributing to total energy intake.