Medium-chain triglycerides (MCT) have unique characteristics relating to energy density and metabolism giving them advantages over more common long-chain triglycerides (LCT). Human consumption of MCT oils is low since naturally occurring sources of MCTs are rare; however, those sources include milk fat, palm kernel oil and coconut oil.

MCTs are less energy dense and highly ketogenic compared to LCTs. First, the energy density of MCTs is less than that of LCTs due to their shorter chain length. MCTs provide about ten percent fewer calories than LCTs; 8.3 Cal per gram for MCTs versus 9 Cal per gram for LCTs. MCTs also differ from LCTs in their metabolic pathway because they are easily oxidized and utilized as energy, with little tendency to deposit as body fat. Consequently, the intake of MCTs can decrease caloric intake and potentially decrease body weight and body fat in the long term.

The literature supports that MCT oil increases energy expenditure and decreases body fat in the majority of studies in both animals and humans. In addition, MCTs may have a greater effect in overweight subjects as opposed to normal weight or obese subjects. Overall, short-term intakes of MCT oil have been shown to promote weight loss; however, chronic intakes of MCTs have shown various effects on energy expenditure, body weight, and fat mass. Yet, appetite control may play a bigger role in weight loss in long-term feedings of MCTs. The exact mechanism for the satiating effects of MCT is unknown, but may perhaps be explained by the distinctive energy density of MCT or the increase in fat oxidation. These studies suggest that replacing LCT with MCT oil could generate body fat loss over long periods of time, with or without reduced energy intake.

Studies provide varying results concerning the influence of MCT on lipid metabolism such as increased TG concentrations. In addition, several studies have reported that MCTs do not affect blood cholesterol levels(94,95,98-100); however, others have reported hypercholesterolemic effects of MCTs due to their high saturated fat content. Therefore, the incorporation of other functional foods, such as conventional oils, essential fatty acids or plant sterol may minimize the risk of negative effects of MCT on blood lipids while optimizing decreases in body weight and body fat accumulation. In addition, the ingestion of MCT incorporated into the diet does not appear to cause any adverse symptoms.

MCTs are easily included in food products without negatively affecting their taste or producing undesirable effects. MCT production is cost-effective compared to other oil-based functional foods. The short-term efficacy of MCT is proven; however, long-term effects of MCT still need to be examined more carefully. Overall, MCT shows a good AECES model and demonstrates the greatest potential for use as a functional fat for weight control.