Whether you're running a 5K or a marathon, the food you eat and the fluids you drink on race day can make or break your performance. Runners know this, of course. But maybe because of the hectic mornings, the rush of endorphins, or the confusing calorie math, mistakes happen.
Race-day fueling is a tricky subject, says Lauren Antonucci, R.D.N., C.S.S.D., owner of Nutrition Energy in New York City and nutrition consultant for the New York Road Runners: On one hand, anything new or different is bad; on the other, you can't just eat like usual. "What's healthiest on a normal day probably won't earn you your best race," says Antonucci. "You have to suspend some of your normal health rules, which is hard to do."
Since every race scenario is different, having experience doesn't necessarily mean you're immune to questionable food-and-drink decisions. The best way to foolproof your day-of strategy? Watch out for these six diet mistakes that afflict even the most well-intentioned runners.
Not Scheduling the Time for Breakfast
"Eating too close to the race can cause cramping, heartburn, and bathroom pit stops," says Kate Sweeney, M.S., R.D., senior clinical dietitian at Brigham and Women's Hospital in Boston and a top age-group triathlete, "and will cause your body to use its energy digesting rather than racing." Skipping breakfast is not an option either: Low blood sugar can cause fatigue and dizziness on the course.
Eat at least 2 to 3 hours before your race starts, says Sweeney. For shorter events, like a 5K, that meal should provide 150 to 200 calories; longer races, like marathons, require much more (500 calories and up). Runners going 10 miles or longer may also need a fist-size snack (like a banana or an energy bar) about 60 minutes before the start to keep blood-sugar levels up. If you need more sleep, "wake up early, eat, and then snooze a bit longer," says Sweeney.
Overdosing on Protein, Fat or Fiber
An egg-and-cheese omelet isn't the smartest prerun choice: Its protein and fat take too long to empty from the stomach and convert to usable energy, and can delay the absorption of the carbs you eat. "Even if you can normally tolerate it before a morning jog, you're likely to be going harder and faster on race day," says Antonucci. Also watch out for high-fiber breakfasts, like whole-grain cereals, which can cause cramping and GI distress.
Eat an easy-to-digest, carb-based morning meal, like a plain bagel with a little peanut butter and a banana, or toast with jam. Oatmeal is a little higher in fiber, but if it has worked for you in training, stick with it. Or try a lower-fiber option like Cream of Wheat.
Drinking All Morning
Dehydration can wreck your race, but so can having to break for the porta potty at mile two (and mile six and mile 12) with a sloshing stomach and full bladder. Drinking too much water without also taking in electrolytes can put endurance runners at risk for hyponatremia, a dangerous loss of sodium.
"Get most of your fluids (about 16 to 24 ounces) at least 90 minutes before the start," says Antonucci, "and then chill out. Take a final six to eight ounces before the race starts." (On very hot and humid days, she adds, plan to slightly increase your fluid intake.) Use the color of your urine as a guide: It should be light yellow, but not totally clear.
Skipping Aid Stations
You're several miles in and feeling great—why waste time walking through a water station or wrestling with a GU? Because by the time you no longer feel great, it may be too late. "During races, we don't get normal hunger signals," says Sweeney. "We often find out by cramping, slowing, or getting dizzy that we didn't fuel or drink properly."
You don't need to chug a full cup at every aid station. But make sure you steal at least a couple of sips every 2 to 3 miles, and take in at least 30 to 60 grams of carbs (120 to 240 calories) every hour after your first 60 minutes of running. Practicing your fueling during long training runs will help you perfect your race-day plan.
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Trying a New Gel
It's hard to predict how your stomach (and your gag reflex) will react to something new in a strenuous environment like a race. No matter how enticing that mocha caramel cinnamon streusel gel sounds at mile 20, today is not the day to sample it for the first time. Best-case scenario, it powers you through until the end; worst case, it powers you straight to the bathroom.
Find out ahead of time what will be served on the course (if the race's Web site doesn't specifically say it, the list of race sponsors may give you a clue). Sample those brands and flavors ahead of time. Or travel with your own trusted nutrition in a pocket or waist belt.
Beelining for the Beer Tent
Congrats, you're done! By all means, you deserve a cold one—but not without refueling with some real food (and plenty of water) first. "Alcohol has a diuretic effect, so the more you drink, the more fluids you actually lose," says Sweeney. Although beer is full of carbs, they're not the best carbs for replenishing glycogen stores and aiding muscle repair.
"You'll recover faster and have a better day, week, and season if you get in some solid nutrition first," says Antonucci. Those postrace bagel and banana freebies will work in a pinch, she says, but a sandwich, yogurt, or protein bar (with a big bottle of water) 30 to 60 minutes postrun is even better.