Myth #9: Fructose is a performance killer

Truth: Fructose can be a performance superfuel

Athletes should embrace fructose.

Athletes should embrace fructose.     Photo: Inga Hendrickson

The warnings are stern: avoid fructose, ­especially in the form of high-fructose corn syrup, because it’s contributing to an obesity epidemic. And the evidence is strong that people who are sedentary should avoid it. But for active individuals, it’s a different story. “All athletes who compete or train for a period longer than 45 to 60 minutes will improve their performance by ­ingesting a ­solution containing carbohydrates,” or sugar, says Luc van Loon, a professor in the Department of Human Movement Sciences at Maastricht University Medical Centre in the Netherlands. And you’ll get more performance bang if that ­sugar is, in part, fructose. When cyclists in a British study drank a beverage containing both fructose and glucose (a simple sugar that typically appears on ­labels as maltodextrin), they rode almost 8 percent faster during a time trial than riders who drank fluids with glucose alone. “Fructose and glucose are ­taken up in the intestine by different transport proteins,” van Loon says. “This allows for a more rapid uptake of carbo­hydrates from the gut.” Which means you have more calories available to you more quickly if you drink or eat carbo­hydrates containing fructose.

Most high-fructose corn syrup contains approximately equal portions of glucose and fructose and is perfectly acceptable for athletes. The concerns about high-fructose corn syrup have more to do with the highly processed foods they often show up in ­rather than the intrinsic characteristics of the ­sugar. The drawback for endurance athletes is that the ideal ratio of glucose to fructose is 2:1 (not the 1:1 of corn syrups). “There are very few drinks on the market that provide that perfect mix,” says Asker Jeukendrup, a professor of exercise metabolism at the University of Birmingham in England, who led the study of cyclists.

Get over it: Read labels. Some drinks, such as PowerBar’s Ironman Performance beverages, tout their 2:1 glucose-fructose mix. For do-it-yourselfers, sports nutritionist Nancy Clark’s homemade sports drink, from the fourth edition of her Sports Nutrition Guidebook, is an ideal performance boost. Gather ­together these ingredients:

1/4 cup sugar
1/4 teaspoon salt
1/4 cup orange juice
2 tablespoons lemon juice

Then, in a quart pitcher, dissolve the sugar and salt in ¼ cup hot water. Add the orange and lemon juice and 3½ cups cold water.

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