Worst Workout Foods: What Not to Eat Before a Workout

To avoid queasiness and hitting the wall, skip these 6 foods before exercise.

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The last thing you want at the gym is an upset stomach, or to tire out 10 minutes in. Reach for the wrong snack and you could doom your workout. Eating foods that sit well and convert to energy efficiently is critical to exercise quality, especially for longer workouts. "Nothing messes up performance like gastrointestinal distress," says Katherine Beals, nutrition clinic director at the University of Utah. To avoid queasiness and hitting the wall, skip these 6 foods before a workout:

Last night's leftovers


Pasta, rice, and potatoes are great carbohydrate sources and tend to settle well for most people, but they're best eaten plain or with a tomato-based sauce, says Beals (one of 22 members of a panel assembled by U.S. News to rate the Best Diets). "I can't tell you the number of people who want to eat pasta [before exercise] and they'll eat a fettuccini alfredo that's really rich, or Indian food, and, boy, do they pay for it," she says. Cream sauces, seasonings, and spices are likely to upset your stomach or trigger heartburn once you start moving. French fries


Potatoes may be good workout fuel, but that doesn't mean you should grab some French fries before the gym. Deep-fried fatty snacks will slow you down, says Manuel Villacorta, registered dietician and spokesperson for the American Dietetic Association (ADA). Avoiding fast food before a workout might be a no-brainer, but even healthy high-fat snacks, like string cheese and almonds, can make you feel sluggish, he says. That's because fat is turned into energy much less efficiently than carbs and protein are. Furthermore, fatty foods commonly cause bloating, according to the Mayo Clinic, which no one wants when they're trying to exercise. High-protein shakes and bars


While protein is an important fuel source and aids muscle recovery, it can be a double-edged sword: Some pre-workout bars and shakes pack high amounts of protein but omit sufficient carbs, and can thus deplete energy levels, says Villacorta. Like fat, protein "doesn't hit the bloodstream quickly, so you can feel tired and shaky even though you have eaten," he says. As a general guideline, aim for a 4:1 carb-to-protein ratio to keep your energy levels up. Veggie salad


A light, veggie-piled salad probably sounds like a great pre-workout meal. Not so much. Lettuce, broccoli, cabbage, cauliflower and other high-fiber vegetables, are common sources of gastrointestinal discomfort, as are nuts and seeds, according to the Mayo Clinic. This fiber bomb can cause real discomfort mid-workout, especially during an activity like biking or running, Villacorta says. Besides being difficult to digest, veggies are mostly fiber, and nuts and seeds are high in fat and protein, so neither provides sufficient carbs for energy. Fruit juices and gels


Guzzling sugary liquids like juices, gels, and sports drinks can cause an upset stomach and diarrhea, Villacorta says. Furthermore, while these simple carbohydrates are great for a quick boost, they won't provide sustained energy. Villacorta recommends using them in moderation and coupled with solid carb options, especially for longer workouts. Avoid citrusy liquids altogether, especially if you have an intense workout planned: They're an invitation for acid reflux. Carbonated drinks


Soda and other carbonated beverages cause gas and bloating for most people. Add to that the excessive amounts of sugar commonly found in carbonated drinks, and you have a recipe for stomach trouble, say experts. While research has found that caffeine can provide an energy boost before exercise, espresso or a small black tea might be more stomach-friendly than a caffeinated cola or carbonated energy drink. Food tolerance varies


Everyone has different tolerances. But exercise can disrupt digestion, meaning foods that normally sit well might not during your workout, says Beals. "The most important thing in doing any pre-exercise meal is that it's familiar and you know it settles well," she says. If you have a big race or rigorous workout planned, make sure you've tried your pre-workout meal before that specific type of exercise to avoid any unpleasant mid-workout surprises. Chelsea Bush writes for AskFitnessCoach, a site with straightforward advice on how to gain muscle and lose weight.