Athletes may consider fat and lipid as a nuisance, though it is an important nutrient. Fat functions not only as an energy source, but also has a unique role in body, and recent researches remind us that. This review describes classical studies and recent findings of fat in sports nutrition.

Choline compound constitutes the cell membrane of our body and acts as a precursor of the neurotransmitter (acetylcholine). It is an important material for the human body. When even the top athlete carries out an intense activity, the internal choline compound is used. And the performance decreases because neurotransmission does not function well. While inspecting these mechanisms, I give an outline of the relations of a choline compound and exercise function.

The objective of the present article is to review literature concerning the effect of supplementation of medium-chain fatty acids (MCFA) on energy substrate metabolism during exercise and body composition. Fat is an energy substrate that is stored in large quantities in the body, and in order to improve the performance and to acquire the body composition desirable for competition characteristics, promotion of fat utilization has been investigated from the aspect of training and diet. Mediumchain triglycerides (MCT) have been attracted attention because they are expected to generate energy easily and promote fat utilization in working skeletal muscle. As a result of studying MCT supplementation by large intake before and during exercise, gastrointestinal discomfort was observed, but the effect on performance was not consistent, and the study was then progressed studying ketone bodies supplementation, which is an intermediate metabolite of MCFA.

On the other hand, continuous supplementation of small amount of MCFA could increase fat utilization during submaximal exercise, improve endurance exercise capacity, suppress the decrease in muscle thickness during off-season, and additively suppressing body-fat accumulation when combined with exercise. In recent years, applications of MCT supplementation for other competitions and exercise modalities are expected as well as class competitions and endurance exercise as cycling.