Use High Glycemic and Medium-Glycemic Carbs for Racing
"Glycemic index is a measure of how quickly carbs get out to the bloodstream," says Applegate. "Something with a high GI is out there and ready for you to use quickly."
Working muscles require fuel, and the first source of fuel your body relies on to sustain your hard training and racing efforts is glycogen, or sugar. Of course, your body is an efficient machine, so it will search for other fuel sources, such as fat, if your sugar stores are low. However, when you switch to burning fat as a fuel source, you'll notice that it's harder to maintain a faster pace when running, swimming, cycling or whatever activity you're doing. You'll ultimately use fat as fuel during endurance events such as marathons or Ironmans, but you'll race faster for longer if you can prolong your body's use of glycogen as the primary fuel source.
More: Best Race Foods
This is why so many marathon runners and triathletes ingest sugary sports drinks, gels, jelly bean-like candies and chews during races. Not only do these fuel sources provide convenient, almost instant energy, but they also provide sugar in an easy-to-tolerate formula that is easy for your stomach to get used to, as long as you've used these products during training. "Fueling yourself with gumdrops while running is fine; it's an acceptable form of fuel that will work," says Applegate. "Sports drinks provide electrolytes too, so there are some benefits to them."
More: Runners and Electrolytes: When to Replace Them
When Applegate competed in long triathlons, she ate cooked rice with dried pears, which she estimated had a medium glycemic index, so energy would be released in a slightly more steady stream compared to the more immediate burst of energy that comes from foods with a high glycemic index.
