In other words, the answer to what you should eat before you exercise is complicated—which is why we asked Jaime Schehr, N.D., R.D., to help break it down for us. The question of working out fasted tends to come up most for people who work out first thing in the morning. I don’t eat beforehand, as my body doesn’t perform well when I do so, but there are plenty of people who do, particularly endurance athletes or people doing strenuous workouts for long periods of time. The way to know if you should? Experiment and listen to your body. If you feel weak, depleted, nauseous, or lightheaded before or during a workout (and you’re already well hydrated), that could be a sign your body needs a little fuel pre-workout. But if you feel fine and, in fact, have more energy not having eaten, then fasted exercise could be a good fit. “Whether or not people eat before their workout is highly individualized,” Schehr says. “Some people need to eat before working out, where others feel best if fasted.” That said, Schehr advises that anyone who is new to exercise have a snack beforehand instead of jumping into fasted workouts. Fasted or not, you have to consume protein after a tough workout—but you probably know that by now, right? On the don’ts list, we have high-fiber and high-fat foods. “If eating before a workout, avoid foods that take longer to digest such as high-fiber raw vegetables and big salads,” Schehr says. “It’s also best to avoid high-fat foods, especially greasy fats. Anyone who needs to eat before a workout will do better if the foods aren’t high fat or high fiber.” Instead, Schehr recommends having a combination of carbohydrates and protein and being mindful of the portion size. “It’s also very important to remember that portion is a factor here,” she adds. “Overeating before you work out can have a negative impact on how you feel during exercise.” Here’s what Schehr says are the best pre-workout foods: “If choosing to eat a bar pre-workout, I would say only eat half before your workout, as they tend to be pretty dense.” Should you want to deviate from the above snack list, Schehr’s rule of thumb is to make your pre-workout portion one-fourth the size of a meal. This baseline will prevent you from overeating but still give you enough juice for an effective workout. The only exception is for people who engage in endurance exercises, like long-distance running, triathlons, or workouts that last more than 90 minutes. “If you’re doing an endurance workout, you may require more carbohydrates throughout the workout compared to strength training, which may require more protein,” Schehr says. “For most exercise, though, I recommend combining a small amount of carbohydrates and protein before a workout.” If you are someone who needs food before exercising, don’t deprive yourself of it. You have to give your body what it needs if you expect it to perform the way you want. “If you’re not eating and you’re exercising, you risk fainting or feeling weak throughout your workouts. This doesn’t mean that everyone needs to eat pre-workout—many people feel better fasted—but it’s important to know your body and what works best for you.”