Let’s say you just had a meal and, lo and behold, you’re struck with the desire to go to the gym. Should you wait a while to exercise after eating, or is it OK to pop on the treadmill right away? Experts say the length of time you wait depends on a few different factors, including what you ate and the type of workout you plan to do.
In general, the more space between a big meal and a tough workout, the better. If you start exercising immediately after eating, it’s possible you’ll experience some uncomfortable digestive symptoms, says Alyssa Wilson, RD, a registered dietician for Signos Health. When undigested foods and liquids jostle around in your stomach, she says it can lead to nausea, acid reflux, bloating, cramping, and even diarrhea.
The timing of your meal and workout can also impact your energy levels, as it’s natural to feel tired or sluggish after eating. “The digestive system requires a lot of energy,” Wilson tells Bustle. “If you eat too close to a workout, all that energy is being used to process the food you just ate instead of being directed to your muscles. This means you may feel a little weaker or slower than you normally would.”
It also takes time for nutrients to distribute throughout your system, she says. If you eat and then try to work out right away, you might not get the full benefits of all your carbs, proteins, and fats. So, how long you should wait to exercise after eating?
It Depends On The Workout
If you just want to go for an easy walk, then the timing of your meal shouldn’t matter. It’ll likely feel comfortable to stroll along at a slow pace after eating — and it might even help with digestion.
According to Steph Magill, MS, RD, CD, FAND, a registered dietician, it’s only when you plan to do an intense or longer-duration workout that you need to think about waiting after eating. It won’t feel good to eat a burrito right before running, swimming, or doing a HIIT workout. “Likely you’ll feel pretty sick and won’t be able to perform well,” she tells Bustle.
“For high-intensity exercise, like HIIT and weight training, where the main goal is to improve performance or gain muscle, it’s important to eat a well-balanced meal with carbohydrates, proteins, and fats before working out,” Wilson adds. But this shouldn’t be done right before you exercise: “While factors like body size, age, gender, and metabolic rate can determine when to eat before exercise, the ideal time for most people to eat is two to four hours before a workout.”
Two to four hours should be enough time to digest before you exercise, Magill says. While digestion is key, you’ll still want to refuel with a quick, easy-to-digest snack before you hit the gym so that you have enough energy to exercise.
It Depends On What You Eat
Not all snacks and meals have the same effect on your body pre-exercise. “Eating larger volumes of food, higher-fat, and higher-fiber foods can all mean that waiting a bit longer may be warranted,” says Brittany Wehrle, MS, RD, CSSD, a sports dietician and owner of Fueled & Well Nutrition. “Larger volumes of food will take longer to digest simply because of the amount of food your digestive tract has to process.”
If you ate something high in fat — think avocado toast or pizza — you may also want to wait a few hours since fat takes longer to digest than the other macronutrients, Wehrle says. Fiber is slow-moving, too. “It slows the passage of food through your digestive system as well — which can be a beneficial thing — but it does mean more resources will be allocated to your gut than your exercising muscles if you eat too much fiber too close to when you exercise.”
Now, let’s say it’s been a few hours since your last big meal, and you really want to work out. Again, that’s when you’ll re-up your energy levels with a quick snack 30 to 60 minutes before your exercise. “During exercise, having adequate available carbohydrates can result in improved performance, lower levels of perceived exertion, and better energy,” Wehrle says. “The general recommendation is to aim for at least 30 grams of carbohydrates, but try to get closer to 60 grams if your workout is going to be very high intensity or last longer than an hour.”
Of course, it isn’t always easy to time your meals and workouts. If you want to wake up, eat breakfast, and work out — and you don’t have time to wait for hours and hours — this is another instance when you could have a smaller meal or pre-workout snack. “You could eat this 30 minutes to one hour before exercise, and would likely not experience any negative effects, like bloating or nausea, during your workout,” Wehrle says.
Some of Wehrle’s fave pre-workout snacks are fresh fruit, a granola bar, a cup of strawberries with yogurt, or a banana with honey. She also suggests having a low-caffeinated drink for a burst of energy. “Keep it simple,” she says, “and make sure carbohydrates are the main component of your pre-fuel snack for best results.”
The consensus is to wait two to four hours after a big meal and 30 to 60 minutes after a snack before working out. That said, always go with what feels best to you. This advice varies from person to person depending on your metabolic rate, your digestive system, what you like to eat, and your fave workout, Magill says — so always listen to your body first.
Campbell, C. (2008). Carbohydrate-supplement form and exercise performance. Int J Sport Nutr Exerc Metab. doi: 10.1123/ijsnem.18.2.179.
Hargreaves, M. (2004). Pre-exercise carbohydrate and fat ingestion: effects on metabolism and performance. J Sports Sci. doi: 10.1080/0264041031000140536.
Steph Magill, MS, RD, CD, FAND, registered dietician