Sports drinks
Sports drinks are high on the glycemic index, which makes them good candidates for mid-race pick-me-ups.

Has anyone ever suggested you eat a Snickers bar for a burst of energy before playing a soccer game or trekking off on a long run? If so, kindly decline, because it's not the best energy food.

Distance runners push their bodies to extremes during 10K and marathon races. It's not uncommon for a distance runner to burn through 1,800 calories during a run [source: Morris]. That's why proper nutrition is a critical element to any training program. But nutrition leading up to race day isn't the only consideration. What you eat during your run could be the difference in how, or even if, you finish.

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Carbohydrates are to the human body's muscles what gasoline is to a car's engine. Carbohydrates are broken down by the body then converted into fuel in the form of glucose, fructose, maltose or lactose. Sugar levels in the blood rise and fall as a result of your carbohydrate intake. In addition, the two main types of carbohydrates -- simple and complex -- act in different ways. Simple carbohydrates rank high on the glycemic index (GI) and are used up faster by your body. Simple carbohydrates give you more energy earlier but will burn off much faster. Complex carbohydrates take longer for your body to break down into useable energy. In other words, you'll have more energy for a longer period of time.

Now that you've prepared for your distance race, it's time to consider what you need during the run. If you've prepared properly, you should have stored enough fuel to get you through the race. But you still need to refuel during your run. Because each run may be slightly different, and you never know how close you are to running out of energy, you want to avoid hitting "the wall." That happens when your body has no more calories to burn. You're out of stored energy. So what you need is something to give you more quick energy.

During your race, eat and drink high GI foods. Obviously you can't run and eat a plate of pasta or rice (both above 90 GI) but you can grab small snacks along the way. Below is a chart with a few high GI foods [source: Glycemic Index Foundation].

 Food GI
 Gatorade sports drink
 GatorLode sports drink
 Rice Krispies
 Power Bar (chocolate, energy bar)
 Rice Chex
 Jelly beans

One mistake many runners make is drinking water in conjunction with sports drinks. Stick to sports drinks. Water dilutes the sports drink, thus decreasing the rate the carbohydrates will break down. Think of what would happen if you mixed cheap 87-octane gasoline with racing gas. The octane level is lowered and the car wouldn't run as fast. The same thing happens within your body when you mix water with sports drinks.

These are just a few foods you can eat during a race. Most of them are small enough to munch on in stride. Runners tend to get into a rhythm during a race, but once the body starts to shut down, you simply can't continue. These foods give you energy faster. Unlike complex carbohydrates, these will get into your system and start producing fuel much quicker. Just remember, you'll use that fuel up sooner so make sure to space out your food intake.

Oh yeah, about that Snickers? It's roughly 40 on the GI. You're better off with a Rice Krispie treat.

Before you run off, don't forget to check out related exercise and running articles on the next page.