Should You Work Out on an Empty Stomach? Here’s What Trainers Say

Beth Ann Mayer
·5 min read
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Group of people working out before eating breakfast

"Food as fuel" has been panned in recent years—deservedly so, frankly. A hallmark phrase of diet culture, it glosses over the idea that food can be delicious and joyful.

But can food fuel your workout to help you achieve your goals and feel your best while doing it? That's been a matter of debate. Influencers may make aesthetically pleasing pre-workout smoothies packed with protein and greens, but you may be someone who experiences cramping or has a tougher workout if you have a meal before a workout.

Food and fitness can get confusing. "Much like a lot of the fitness and nutrition world, there is a ton of conflicting information out there," says Rebecca Stewart, ISSA CPT and Mobility Coach and founder of MovementFX.

However, settling the score on this topic once and for all can help you hit your goals. "Knowing whether or not to work out on an empty stomach can make the difference in how your workout feels and how your body performs," Stewart says. "Whether you eat before a workout can also impact your recovery and how much you enjoy your exercise session. Potentially most importantly, it can also impact your fitness progress and the results you see."

So which is it? Should you work out on an empty stomach or not? Experts share the truth.

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Should You Work Out on an Empty Stomach?

"Without question, you will always perform better in a fed state," Stewart says,

Another trainer agreed. "The simple answer is no," says Louise Hazel, CPT, an Olympian and CEO of SLAY.

Michelle Ditto of Purre Barre elaborates further, saying, "Exercise requires energy, and energy comes mainly from what we eat. Your muscles require fuel to exert optimally, and having energy to use in that exertion is key to reaching the goals you may have."

Ditto adds that sleep, hydration and hormones matter too, but it's important not to overlook eating for another reason.

"Training fed, or eating before a workout, can facilitate muscle strengthening in the form of progressive overload, especially in the last few repetitions of a movement that are meant to push you to the point of fatigue," Ditto explains.

The caveat? Stewart says if a pre-workout meal isn't for you, then you can probably skip it. "As long as energy levels remain stable and you’re able to get through the workout without a dip in performance, it should be fine for most people to workout on an empty stomach," Stewart says.

A caveat to the caveat: "Exercise can lower blood sugar, so people with type 1 diabetes should only do fasted workouts under the guidance of their endocrinologist," says Trish Gomez, RD, LDN, CPT. "Pregnant women should speak to their OBGYN before starting fasted workouts. Anyone with a chronic illness should discuss these decisions with their healthcare provider."

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Does Eating Before a Workout Actually Help With Weight or Fat Loss?

It's unclear. A small study of white men from 2014 suggested that pre-workout fasting could help with weight management, but a 2016 study of 20 women found no difference between those who did or didn't eat before a workout.

"Research indicates that when individuals exercise fasted, they consumed fewer calories throughout the day, but also burned fewer calories, resulting in no weight loss," says Gomez. "However, regularly working out while fasting can improve insulin sensitivity, glucose management and muscle metabolism, which may make weight loss efforts more successful, especially for those who are insulin resistant, type 2 diabetic or obese."

More research is needed to say for sure. In the meantime, experts suggest a holistic approach. "Working out on an empty stomach can burn more fat, but consider the cost and consider what you are working out for," Ditto says. "Fitness is good for so many other things beyond fat loss."

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What an Olympian and Personal Trainer Eats Before a Workout

Hazel, who competed with England in the 2012 Olympics in London, shares her pre-workout playbook.

"I prefer pre-workout snacks to a full meal that might sit heavy on your stomach, especially if you have an intense workout scheduled," Hazel says. "You want to aim for at least 30 grams of carbohydrates to fuel your workout."

Some of her go-tos include:

  • 1 medium banana (5 oz.)

  • 1 slice of toast (2 oz.)

  • 1 cup of cooked oatmeal (9 oz.)

  • 1 fruit yogurt (8 oz.)

  • 1 protein bar (2 oz.)

When Should You Eat Before a Workout?

It depends on whether you're talking about a meal or a snack.

"If you workout in the morning, eat at least a snack with carbohydrates and protein before exercise," Stewart suggests. "If you’ve just eaten a full meal, it can be ideal to wait two to three hours before an intense workout to give your body time to digest."

What about a snack in between meals?

"If you’re working out in between meal times, eat a snack 30-60 minutes before exercise," Stewart says. "Having that food in your system will help give you the energy to have a productive workout."

Next up: 10 Easy Strength-Training Workouts That Will Help You Live Longer

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