Burke, L. M., Angus, D. J., Cox, G. R., Gawthorn, K. M., Hawley, J. A., Febbraio, M. A., & Hargreaves, M. (1999). Fat adaptation with carbohydrate recovery promotes metabolic adaptations during prolonged cycling. Medicine and Science in Sports and Exercise, 31(5), Supplement abstract 297.

Trained cyclists (N = 8) consumed either a high-carbohydrate diet (9.6 g/kwBW CHO; 0.7 g/kgBW) or an isoenergetic high-fat diet (2.4 g/kgBW CHO; 4.0 g/kwBW fat) while training. On day 6, a high-CHO diet and rest was used to restore muscle glycogen before testing (two hours of cycling at 70% VO2max) on day 7.

The high-fat diet increased fat utilization, recording higher values for fat oxidation and lower values for CHO oxidation. Time-trial performance was better for the fat diet. None of the between-groups differences were statistically significant.

Implication. Perhaps the fat diet might assist performances in endurance cycling but until unequivocal results are demonstrated, the results of this study must be viewed cautiously.

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