Keep in mind, well-trained muscles can readily take up carbohydrates from the blood stream. Hence, athletes need less insulin than unfit people. This means athletes have a lower blood glucose response to what would otherwise create a high blood glucose response in an unfit person. Exercise is very important to manage blood sugar -- and help prevent Type II diabetes.
All things considered, you, as an athlete, have little need to concern yourself with a food's glycemic effect because you don't even know your personal response to the food. Plus, research of exercise scientists fails to clearly support the theories mentioned above. The research does indicate the best way to enhance endurance is to consume carbs before and during exercise -- tried-and-true choices that taste good, settle well and digest easily. Hence, you need not choke down low-glycemic-index kidney beans thinking they will help you with sustained energy, when they actually might only create digestive distress! Simply plan to consume about 200 to 250 calories of carbs each hour of endurance exercise, and you'll enhance your performance.
For athletes who do double workouts or compete more than once a day, choosing a high-glycemic-index food for recovery might be a wise choice. Theoretically, it provides glucose quickly, more rapidly refuels depleted glycogen stores, and enhances subsequent performance. But, research does not show performance benefits. According to Beals, the more important task is to eat enough carbs (or carbs with a little protein) as soon as tolerable, post-exercise. What's enough? 0.5 g carb per pound of body weight -- about 300 calories for a 150-pound person, in repeated doses, every two hours.
Insulin and "fattening carbs"
There is a popular myth that high-glycemic-index foods are fattening because they create a rapid rise in blood sugar, stimulate the body to secrete more insulin and thereby (supposedly) promote fat storage. This is wrong. Excess calories are fattening, not excess insulin. Dieters who lose weight because they stop eating high-glycemic-index foods lose weight because they eat fewer calories. A year-long study with dieters who ate high- or low-glycemic index meals indicates no difference in weight loss. (2)
Sugar highs and lows
Some athletes claim to be sugar sensitive; that is, after they eat sugar they report an energy "crash." If that sounds familiar, the trick is to combine carbs with protein or fat, such as bread and peanut butter, or apple and low-fat cheese. This changes the glycemic index of the carb.
By experimenting with different types of snacks, you might notice you perform better after having eaten 100 calories of yogurt (a low-glycemic-index food) as compared to 100 calories of high-glycemic-index rice cakes. Honor your personal response when choosing foods to support a winning edge for your body.
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