Endure: Mind, Body, and the Curiously Elastic Limits of Human Performance

by Alex Hutchinson

If that’s the case, then it makes sense for endurance athletes to stock up on carbohydrates as much as possible. And that, more or less, is what sports nutritionists have been advocating since the 1970s. Keep your glycogen levels high by consuming a diet that gets 60 to 65 percent of its calories from carbohydrate; top up your stores by carbo-loading in the final few days before a competition; and in events lasting longer than about ninety minutes, eat or drink some easily digested carbohydrates to supplement your stored glycogen, which will otherwise run out. (Modern sports nutrition guidelines, Hawley points out, actually recommend a daily target amount of carbohydrate per pound of total body weight based on the type of training you’ve done that day, rather than overall percentage targets. This helps account for the considerable differences between the needs of, say, an elfin distance runner and a heavyweight rower.)