High Fat or Low Fat Diets For Endurance?

Question: Will, as a competitive cyclist I am interested in the higher fat low fat debate for athletes like myself. In particular, I wonder if I should use a high carb low fat sports bar on long trips or one of the newer higher fat moderate carb bars. What do you recommend ? All the best, Robert Moore

Answer:

Robert, I cant cover the entire debate over higher fat vs lower fat diets here in this QnA. I can however give you some insight into the debate by focusing briefly on a study that looked at exactly what you are asking regarding which bar an endurance athlete might want to use. Certainly the past year or so has seen a dramatic increase in the debate over whether a high carbohydrate/low fat diet versus a higher fat/lower carb approach is superior for athletic performance. As expected, various brands of sports bars that emphasize different ratios of fat, protein, and carbohydrates, have hit the market for a variety of uses.

Researchers from the Exercise and science Lab at Central Washington University (Medicine and science in Sports and Exercise, Vol. 29, No. 5, p[s]250, 1997) put some bars to the test containing different amounts of carbs, protein, and fats. Using well trained cyclists doing 60km time trials, the study found that bars containing the highest ratio of carbs to fats (76% carbohydrates, 15% protein, 8% fat) fared poorly against the bars containing more fats and proteins and less carbs in the times of these athletes. When the athletes were fed the bars containing at least 30% fat (or more), 40% carbohydrates, and 30% proteins, one hour before exercise, they finished 2-4 minutes faster on the 60km time trial than when they were fed the high carb/low fat bars. Something to consider on your next Tour de France.