Should You Eat Before Or After A Workout? Experts Weigh In

It can be tough to decide whether you should eat before or after a workout. On the one hand, it makes sense to fuel up so you have enough energy to exercise. On the other, it makes sense to wait so you aren’t jostling around on a full stomach. And so there you stand, smoothie in hand, wondering if it’s a pre- or post-workout kind of meal.

Well, as it goes with any nutrition or exercise question, there isn’t a perfect, one-size-fits-all answer. Everyone is different when it comes to how they feel about eating before and after workouts, says Sandy Sweeney, a trainer and owner of Burn Boot Camp Hainesport, New Jersey. And it also depends on factors like what type of workout you’re about to do, how long you plan to work out, and when you had your last meal.

If you had dinner an hour ago and feel like going for a bike ride, don’t overthink it. Dr. Mohammed S. Alo, DO, a cardiologist and certified personal trainer, says there’s no need to think too hard about what and when you’re eating if you just have the urge for a casual exercise session. But if it’s first thing in the morning and you want to squeeze in an hour-long strength training workout before work, that’s when you might want to ponder your nutrition. Here’s what experts have to say about eating before or after a workout and how each will affect your body differently.

Eating Before A Workout

The food you eat shortly before a workout functions as your fuel. “Your body will use the glycogen from that food source for energy,” Sweeney explains. Glycogen, BTW, is a form of sugar. “You can store some in your muscles, but it’s not a lot and can be depleted quickly,” says Alo. Essentially, when you need energy, your body first taps into sugars in your bloodstream, he explains, which run out pretty quickly. From there, it hits up your muscle glycogen stores, then energy stored as fat.

If you’re exercising first thing in the morning and haven’t eaten in 10 hours, your body is considered to be in a fasted state. That means it won’t have the right fuel, or the right amount of glycogen, to get through your routine. “Working out on an empty stomach, especially if your muscles are depleted of glycogen, makes the workout less productive and you may get fatigued and not get to enjoy the full benefits of a heavy and hard workout,” adds Alo.

Sure, you may feel OK for the first few minutes, but you’ll quickly start to run out of steam. “Your muscles being depleted of glycogen and being fasted can make it so that you can't do as many reps or as many sets or can't go as long in your HIIT or cardio workout,” Alo says, which is why it’s recommended that you get a little something in your system first.

What To Eat Before A Workout

For a bit of pre-exercise fuel, Alo recommends eating fast-absorbing carbs to give you a quick burst of energy, as well as slow-absorbing carbs for more sustained energy. “Things like oatmeal can go a long way to power your workout, as well some easily-absorbed sugars like a fruit juice or some of those pre-workout drinks [that have sugar and some caffeine],” he says. “You could also eat fruits and fibrous vegetables, which will help power your workout so that you can exercise longer and stronger.”

If you’re worried about exercising on a full stomach, keep it light with a pre-workout snack. A banana, a granola bar, or even a piece of toast with peanut butter and jam are all good options, says Dr. Suzannah Wong, DC, a chiropractor and health expert. If you plan on doing cardio or working out for a long period of time, she suggests topping it off with a carb-based beverage for even more energy. You could also have a snack mid-way through the workout if you start to feel fatigued.

Planning on strength training? Experts suggest adding a little extra protein to your snack. “Protein generally digests slower than carbs and therefore will last when doing a strength workout that requires more effort from your muscles,” says Sweeney.

When To Eat

If you’re about to do light exercise, like an easy incline walk on a treadmill, it’s recommended that you eat 30 minutes to an hour beforehand. “This [amount of time] allows the food to get into your system and your blood sugars to start rising, which is what gives you the energy to train,” says Wong.

If you’re about to do something that requires more exertion — think CrossFit, weight training, running, etc. — try to eat two hours before. “This gives the stomach enough time to digest the food, absorb the sugars, and pass it along to your small intestines,” Alo says. But remember, do what feels right for you.

Eating After A Workout

Your post-workout meal is what’ll help refuel your body. “Getting a combination of protein and carbs is important as it helps your muscles to rebuild and helps to restore your glycogen levels,” Wong says. That translates to a quicker recovery.

This post-workout meal will also help you build muscle. “If you are an intermediate weightlifter or an advanced athlete, then replenishing your glucose and glycogen stores after a workout is very important,” says Alo. Building muscles is all about aiding this recovery stage, he says, which is why it’s often recommended to eat carbs and protein after lifting.

For reference: Strength training and other difficult workouts essentially tear down your muscle fibers, Sweeney explains. “The regrowth of the fibers are important for building lean muscle tissue,” she says. That’s where your post-exercise fuel comes into play.

What To Eat

If you just did cardio, Sweeney recommends replenishing your energy levels with some plant-based carbs. Think whole grains, fruit, veggies, legumes, or starchy foods like potatoes. If you just did strength training, add in some protein. “Proteins are the key here post workout,” she says, pointing to proteins that contain BCAAs (branch chain amino acids), which come from both animal and plant sources (including beef, chickpeas, lentils, and fish).

When in doubt, aim to have a meal that contains both protein and carbs. “Ideally, a meal that has all your macronutrients will be best,” Sweeney says. “That would include good carbohydrates from veggies, clean protein, and a little healthy fat-containing omega 3s.”

When To Eat

One thing to keep in mind is that you may not feel like eating immediately after a workout. “Your digestive system, for example during a HIIT or intense cardio session, will slow down or shut down because your body thinks it is in a stressful situation,” Sweeney explains. Since it may take some time for your adrenaline to calm down, you may find that it feels right to wait about an hour post-workout.

If you’re training with specific goals in mind — for strength or endurance, for example — you may want to get some BCAA proteins in your body ASAP. “It is best to get these sources back in your body as early as 20 minutes post-workout and up to one hour,” Sweeney says. “But protein needs and amounts are different for everyone and also dependent on individual goals.”

The Takeaway

Fueling and recovering are equally important if you want to make the most of your workout routine, Wong says. Of course, everyone is different when it comes to how they feel before, during, and after exercise, as well as how serious they are about their fitness goals. Sometimes, you just want to fit in some movement, have a snack, and move on with your day — and that’s OK. The bottom line, according to Sweeney, is to experiment and find what feels best for your body.

Studies referenced:

de Oliveira, EP. (2009.) The impact of physical exercise on the gastrointestinal tract. Curr Opin Clin Nutr Metab Care. doi: 10.1097/MCO.0b013e32832e6776.

Ivy, J. L. (2004.) Regulation of muscle glycogen repletion, muscle protein synthesis and repair following exercise. Journal of sports science & medicine.

Jensen, J. (2011.) The role of skeletal muscle glycogen breakdown for regulation of insulin sensitivity by exercise. Frontiers in physiology. https://doi.org/10.3389/fphys.2011.00112.

Murray, B. (2018.) Fundamentals of glycogen metabolism for coaches and athletes. Nutrition reviews. https://doi.org/10.1093/nutrit/nuy001.

van Vliet, S. (2018). Achieving Optimal Post-Exercise Muscle Protein Remodeling in Physically Active Adults through Whole Food Consumption. Nutrients. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5852800/

Experts:

Sandy Sweeney, trainer

Dr. Suzannah Wong, DC, chiropractor, health expert

Dr. Mohammed S. Alo, DO, cardiologist and certified personal trainer