How to Fuel Your Workout

Reviewed by Sharon Denny, MS, RDN

Which is better fuel for spinning class—protein or carbohydrates? Should you consume a sports drink on a long run? Is it safe to eat before a workout? Listen to locker room talk at the gym and you'll hear lots of conflicting tips about what you should eat and drink before and after you work out. These answers to five common questions about fueling your workout sort fact from fiction.

Protein is an important part of a balanced diet, but eating more protein will not magically make you stronger. The only way to grow muscles is to put them to work. "Carbohydrates are the best fuel for working muscles," says Academy of Nutrition and Dietetics Spokesperson Heather Mangieri, MS, RDN, CSSD.

Carbohydrates are partially converted to glycogen, which is stored in your muscles to power your workout. "Fifty to sixty percent of energy used during one to four hours of continuous moderate to hard endurance activity is derived from carbohydrates," says Mangieri.

There's nothing special about the many sports drinks, gels and energy bites on the market. But it is important to replace lost fluids and provide carbohydrates to maintain blood glucose levels while working out. "Gels, energy bites or sports drinks can be an effective way to supply the body with energy, but they are not necessary. Real food will provide the same benefit as these pre-designed workout fuels," says Mangieri.

For some athletes, eating solid food in the middle of a workout can cause digestive upset. In these cases, easily consumed sports gels, chews or drinks may help. "Food and fluid intake around workouts should be determined on an individual basis with consideration for an athlete's gastrointestinal tract tolerance, as well as duration and intensity of the workout," says Mangieri.

Your body needs fuel to function, especially if you're asking it to run, jump, swim or lift weights. Don't skip breakfast. "Eating before exercise, as opposed to [exercising in] the fasted state, has been shown to improve exercise performance," says Mangieri.

Eating in the morning helps replenish liver glycogen and steadies blood sugar levels. If it's hard to stomach solid food first thing in the morning, try a fruit smoothie, or a liquid meal supplement, and don't forget to hydrate before you exercise.

Wrong. Working out isn't license to abandon portion sizes and healthy eating guidelines. It's easy to overestimate the amount of calories you burn while working out.

You should adjust your calorie intake if you’re engaging in serious training, such as for a triathlon, where you might be working out more than once a day. "Recovery nutrition is necessary if you are an athlete participating in strenuous activity, especially if you are participating in multiple events in the same day," says Mangieri. "For the casual exerciser working out for an hour or less, a healthy balanced diet will work just fine."

Because of its favorable carbohydrate and protein content, chocolate milk is indeed an effective recovery aid, but it's not your only choice. "Yogurt or half a turkey sandwich on whole wheat can be just as effective," says Mangieri.