Despite its limitations, nutritionist Gidus suggests that an athlete fine-tune her food intake with the GI. “I recommend eating low-GI foods before exercise to provide a more sustained energy release. Moderate- to high-GI foods are best during and post-exercise for immediate repletion of glycogen,” she says.
· Before: apples, plums, cherries, peanut butter, milk, yogurt
· During: grapes, sports drinks and gels
· After: bagels, potatoes, juices, sports drinks and gels
The GI doesn’t tell it all, however. It measures the effect that 50 grams of carbs in a particular food has on blood sugar, but it doesn’t factor in the relative amount of carbs in an average serving of that food. That’s why some nutritionists use the glycemic load (GL) instead. Watermelon, for example, has a high-glycemic index because 50 grams of carbohydrate in the fruit has a large effect on blood sugars. But since a typical slice contains only about 6 grams of carbs, watermelon’s GL and it’s effect on blood sugar is small. The same is true for carrots. They have a high GI, but a low GL.
For more info and to find out GI/GL values of certain foods, search the GI Database on glycemicindex.com. Experiment with different pre- and post-exercise meals to learn your best strategy. The glucose response varies from person to person and even from meal to meal.
From the March/April issue of Her Sports + Fitness,written by Jill Weisenberger, M.S., R.D., C.D.E.
