Effect of fat adaptation and carbohydrate restoration on metabolism and performance during prolonged cycling

Abstract

For 5 days, eight well-trained cyclists consumed a random order of a high-carbohydrate (CHO) diet (9.6 g·kg-1·day-1 CHO, 0.7 g·kg-1·day-1 fat; HCHO) or an isoenergetic high-fat diet (2.4 g·kg-1·day↑ CHO, 4 g·kg-1·day-1 fat; Fat-adapt) while undertaking supervised training. On day 6, subjects ingested high CHO and rested before performance testing on day 7 [2 h cycling at 70% maximal O2 consumption (SS) + 7 kJ/kg time trial (TT)]. With Fat-adapt, 5 days of high-fat diet reduced respiratory exchange ratio (RER) during cycling at 70% maximal O2 consumption; this was partially restored by 1 day of high CHO [0.90 ± 0.01 vs. 0.82 ± 0.01 (P < 0.05) vs. 0.87 ± 0.01 (P < 0.05), for day 1, day 6, and ..