Fuel for thought
Your main goals in eating before a workout are to stay hydrated and to fuel your exercise. One of the most common mistakes people make is overestimating how many calories they’ll need. Generally, Bonci says, you’ll want to make sure to eat within two to three hours of a workout. But you don’t need much—around 200 calories will do it for a typical moderate- to high-intensity one-hour session. For that reason, and especially if you’re trying to lose or maintain your weight, she suggests incorporating that pre-workout nosh into a meal or splitting your meal to eat half before your workout and half after. That way, you’re less likely to overconsume calories.
If you don’t eat or hydrate enough before a workout, you may not have the stamina to keep pushing through. But if you eat too much, it can divert blood away from your muscles to your digestive system, slowing you down. You need to strive for a happy medium. Bonci says about 14 to 20 ounces of liquid an hour before you exercise is a good rule of thumb. And as far as food goes, you’ll want a mix of protein and carbohydrates for fuel. “What you eat before you work out won’t be immediately available as an energy source for you,” says Bonci, “but it will help prevent hunger and keep your body from tapping into muscle stores to get energy.” Read on to find out which foods, including some normally healthy ones, you should avoid pre-workout.
Your body needs carbs as a quick source of energy, but you can easily overdo it. “Carb loading doesn’t mean carb bloating,” says Bonci. You want a moderate amount of complex carbohydrates (whole grains over white pasta and bread), and you need enough fluids to help your body use those carbs as an energy source.