You want to have enough energy to really push in your after-lunch workout, but worry that a meal might make you nauseous. Is it OK to exercise after you eat, or should you fast until your workout is over?
For many people, exercising strenuously on a full stomach can lead to reflux, hiccups, nausea and vomiting, said Dr. Daniel Vigil, health sciences associate clinical professor at the University of California, Los Angeles. But there are some people who can eat a big meal and experience no issues when they exercise afterward, Vigil said.
Research, on the other hand, shows that eating before exercising is not ideal. The best time to work out, Vigil said, is before you eat. A post-exercise nutrition program helps recovery and minimizes muscle damage, Virgil said. Plus, a recent study published in The American Journal of Physiology found that men who exercised without eating beforehand burned more fat.
However, if your schedule demands you eat first, Vigil suggestsed waiting an hour or two after your meal before exercising. That will allow the stomach to empty out.
Of course, that rule changes if you’ve overeaten.
“If you’re going to sit down to a Denny’s Grand Slam Breakfast, it’s going to be in your stomach for a lot longer,” said Leslie Bonci, director of sports nutrition at the University of Pittsburgh Medical Center. “My general rule of thumb for my athletes is to wait an hour before exercising. And you want to keep the amount of food to about the size of your fist, not the size of a football.”
Bonci suggested tailoring what you eat to the kind of exercise you’ll be performing. So, if you’re going to be running, drink about 20 ounces of liquid an hour beforehand, she says. And eat something small and carbohydrate-based, such as a granola bar, a banana or some dry cereal.
If you’ll be doing hot yoga, “you don’t want to start dehydrated,” Bonci said. “It’s not so energy expending as running, so you could do 8 ounces of juice and 12 ounces of water,” she said.
“If you’re going to be doing some degree of strength training — and that’s not just weight lifting, but also swimming since that’s got a strength component — it’s critical to have some protein. I’m not talking about a pound of bacon and a dozen eggs. The maximum should be 20 grams of protein. That could be 8 ounces of yogurt or 6 ounces of yogurt with some cereal on top of it.”
Swimmers, she says, should get a combination of protein and carbohydrates. “You might try a bagel thin or sandwich thin with two eggs and a little cheese,” she suggested. “It’s not a huge volume, but it provides some protein and carbohydrates.”
Those who will be biking “need to take the gut into account and think about what it’s going to feel like to be crouched over for a long time,” Bonci said. “You may not feel comfortable with an omelet in your stomach and even a 6-inch sub may be pushing it.”
If you’re hoping to get a little extra fuel in the tank right before working out, or, say, between two halves of a soccer game, Vigil said it’s generally OK to boost your energy with 100-200 calorie sports bar.
Linda Carroll is a regular contributor to NBCNews.com and TODAY.com. She is co-author of "The Concussion Crisis: Anatomy of a Silent Epidemic” and the recently published “Duel for the Crown: Affirmed, Alydar, and Racing’s Greatest Rivalry”