I did intermittent fasting (IF) for a little over a year, and one question I often had was whether it was OK not to eat after a workout. Would I sabotage my goals of building muscle and losing weight if I skipped my post-workout snack? I usually worked out in the morning, as early as 5:30 a.m., but my eating window didn't start until noon. It's one thing to wait an hour for a post-workout snack, but six seemed like a stretch.
This isn't just a fasting-related question, either. Whether you do IF or not, sometimes you just aren't hungry after a workout. In general, listening to your hunger cues (eating when you're hungry, not eating when you're not) will lead you in the right direction, but we also constantly hear how important it is to refuel your body after exercise. So just how important is it to eat after your workout – and what do you do if you don't feel like eating?
What Happens If You Don't Eat After a Workout?
You may have heard something about what not eating after a workout can do to your body, but it's worth a quick refresher. During a workout, you're breaking down muscle, actually creating small micro-tears in the tissue. That breakdown process is what makes it possible to build your muscles and help them grow bigger and stronger, but only if you refuel correctly with nutrients like protein, which helps to repair that damage. Registered dietitian Michele Fumagalli, LDN, from the Northwestern Medicine Running Medicine Clinic, told POPSUGAR that failing to fuel after a workout can push your body into a catabolic state, where it's breaking down muscle mass and slowing down your metabolism - the opposite of what you want.
You'll also need to eat carbs, especially if your workout involved cardio. Your body uses glycogen - stored glucose - as energy to fuel your workouts, and it gets that glucose by converting carbohydrates. Rebuilding the supply gives you the energy to recover from your workout and keep going through your day.
How Long Can You Wait to Eat After a Workout?
When determining how soon you need to refuel after a workout, there are a few different factors you have to take into consideration. The first, Fumagalli said, is how recently you've eaten before the workout.
For example, let's say you stop eating at 8 p.m., then wake up the next morning to do a 6:30 a.m. fasted workout - no food beforehand. The period after that workout, particularly if it involved strength work or high-intensity interval training (HIIT), is a crucial time for refueling, Fumagalli said. If it's been several hours since you last ate, replenishing your body will prevent it from breaking down muscle mass, allowing it to start the repair and recovery process instead. This also applies if you have a short recovery window between workouts; if you're doing "two-a-days," for example, or working out at night and then early in the morning.
"The pre- and post-workout food align," Fumagalli said. "Whatever you ate at lunch or even at breakfast is going to help you through your workout and post-workout." If you haven't eaten beforehand, it's crucial to refuel within an hour of working out. But if you had a meal two hours before your workout, Fumagalli explained, "you can probably wait an hour or two to eat your next meal."
Regardless of your pre-workout food, Fumagalli said it's usually fine to wait 30-45 minutes to eat after a workout. What you don't want to wait on is hydration. "We need to make sure we're drinking a lot of fluids, primarily water or water with electrolytes," Fumagalli said. The electrolytes are especially important for cardio workouts that lasted an hour or longer, according to registered dietitian Kristin Kirkpatrick of the Cleveland Clinic's Wellness Institute.
Should I Eat Even If I'm Not Hungry?
With all of that in mind, Fumagalli said that it's crucial to eat within at least two hours of a workout – regardless of whether you're hungry or not. And, yes, that includes those of us doing intermittent fasting. That doesn't mean you have to break your fast early every day, though you may want to if you're not scheduled to eat for more than two hours after exercise. If you want to stick to your fasting schedule, it'll be about structuring your eating and workouts so that you're able to refuel within that two-hour window.
Kirkpatrick added that if you're doing 5:2 intermittent fasting (eating regularly five days a week and restricting to 500 to 600 calories for the other two days), you may want to avoid working out at all on your fasting days. "The whole purpose of time-restricted eating is to limit your consumption to no more than 8-10 hours," Kirkpatrick told POPSUGAR. "You really have to plan to set your workout and fueling needs around that."
If you're simply not hungry after a workout, Fumagalli still recommended eating at least some protein and carbs. It's not necessarily that your body doesn't want the food; she said you might not be hungry post-exercise simply because "your body isn't used to getting food right after your workout. You might just get accustomed to that routine." It doesn't have to be a full meal; even a smaller snack can shore up your carb stores and keep your body from going into that catabolic state of muscle breakdown.
Foods to Eat After a Workout
It's best if you can eat a full meal within two hours of exercise, Fumagalli said, complete with protein, carbs, and vegetables, but that's not always possible, and might not even sound good right after a workout. In that case, Fumagalli said a protein shake can be a good option. "They're great for convenience," she explained, if you know you're not going to be able to sit down for a meal for a few hours, or if you just don't feel like eating a full meal. Make sure to eat a piece of fruit, such as a banana, on the side or throw it in the smoothie itself. Many packaged protein smoothies don't have any carbs, Fumagalli said, but they're essential for recovery as well.
Protein-Rich Foods to Eat After a Workout
If you're going straight from the gym to a meal, though, there's no need to push the extra protein: just make sure you have a good source of it on your plate, as well as carbs and vegetables. If you're looking to increase your strength and avoid muscle breakdown, Kirkpatrick recommended protein-rich foods like:
Carbohydrates to Eat After a Workout
After intense cardio workouts, it's especially important to replenish your supply of glycogen by eating carbs. Kirkpatrick and Fumagalli recommended:
Low glycemic index (GI) fruits like apples, pears, berries, or cherries (GI measures how much a certain food raises your blood sugar levels.)
And while your post-workout fuel is important, remember that it's only a portion of your everyday diet. "Just a pre- or post-workout meal isn't going to help you as much as if you're consistently eating healthy and balanced," Fumagalli said. This is particularly important if you have specific goals you're focused on, such as losing weight or building muscle. You should plan out all of your meals and snacks with those objectives in mind, not just what you eat after your workout. "This is just one meal out of three that you're eating," Fumagalli explained. "It's important to look at the bigger picture too."