Impact of fat adaptation on metabolism and sport performance:A review of the current evidence

A combination of diet and sports training plays a major role in athletic performance. One diet-related strategy that has garnered attention is fat adaptation. This study reviewed the current evidence on fat adaptation and performance. PubMed was searched for information on the use of fat adaptation، fat adaptation and performance، high fat diet and performance، and fat adaptation and athletes for the years 1994 through 2012. It was found that، in most studies، fat adaptation with carbohydrate restoration increased fat oxidation independently of exogenous and endogenous carbohydrate availability and decreased carbohydrate oxidation. Some studies reported increased muscle triglyceride stores and the activity of hormone-sensitive lipase and enzymes for triglyceride hydrolysis. A reduction in muscle glycogenolysis without a change in plasma glucose oxidation was also observed. Some studies indicated that a decrease in glycogenolysis might negatively affect high intensity exercise، and a high carbohydrate oxidation rate appeared to be essential for optimal performance in such sports. Most studies indicated favorable metabolic changes following fat adaptation، but did not provide clear benefits for performance. More research is needed to identify the mechanisms related to fat adaptation and exercise intensity. Furthermore، the large inter-individual variability to fat-adaptation strategies must be determined.