The Mistake: Loading Up on Fiber
Normally, runners should make sure to eat lots of cruciferous vegetables, beans, and whole grains. And if you're used to such foods, all that roughage right before a race may pose no problems for you. But if you've been living on pizza and burgers, now is not the time to become a vegan. Loading up on high-fiber foods can cause uncomfortable gas, especially if your stomach is plagued by pre-race jitters.
The Fix: If you think fiber might be an issue, "cut back on those foods three days before a major race," says Gidus. That includes beans and bran cereals-but not fruits and veggies, which you should eat in modest portions. Think one cup of pineapple, a handful of cherries, or a few broccoli florets. But, Gidus cautions, if you're racing every weekend, reduce your fiber intake only on race day to make sure you don't trim all fiber out of your diet.
More: The Truth About Fiber
The Mistake: Skipping Breakfast
Too nervous or worried about feeling full, some runners can't face food on race morning. But without it, you're likely to bonk in any race. Why? Because studies show that a pre-race meal keeps your blood sugar steady and provides energy to power you through. "There's no way to get enough fuel midrace to make up for the energy you missed at breakfast," says Jauquet.
The Fix: If you know you get too nervous to eat before a race, wake up a few hours before the start-so you can eat breakfast slowly, letting each bite settle before taking another. If you can't stomach solid foods, drink a smoothie with bananas, fruit juice, and milk. These ingredients are easy on most stomachs, provide energy, and won't leave you feeling overly full.
More: The Pre-Race Meal
The Mistake: Trying Something New
If you've never had spicy salmon sushi, don't order it the night before your race. You won't know how a food affects you until you've tried it-and last-minute experimentation could send you bolting for the bathroom and leave you dehydrated.
The Fix: Stick with what you know for a week before race day. Check the race Web site to confirm which drinks and gels (if any) will be offered along the course so you can test them out in advance. Don't be afraid to skip the pre-race dinner or hotel breakfast: If you're not used to downing sausage burritos pre-race, you're better off sticking with a familiar bowl of pasta. As long as it isn't huge.
In the days before a race, vary your diet with non-grain carb sources, such as fruits and starchy vegetables, to benefit from a wider range of nutrients.race.