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10 Fast-Digesting Carbs to Eat for a Quick Pre-Workout Boost

Top off your gas tank as you prep your body for exercise.

By Jessica MigalaJanuary 31, 2025

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Workout starting soon but you’ve got little time to fuel up? Enter: fast-digesting carbs. These foods can give you the pre-exercise energy kick you need to crush your sweat session—and they may be useful in recovery too. 

That said, not everyone needs fast-digesting carbs before a workout. They’re best in certain scenarios, and whether or not you should eat them depends on a host of factors. Learn more about fast-digesting carbs, including what they are (and how they differ from a complex carb), when you should eat them, the best simple carb picks, and more tips to make them work for you.

What Are Fast-Digesting Carbs?

Also called simple carbohydrates, “fast-digesting carbs are foods that quickly break down into glucose, providing a rapid source of energy,” explains Kristy Baumann, RD, registered dietitian and founder of Marathon Nutritionist. These carbohydrates are low in fiber and fat, making them easy—and quick—to digest so they can provide glucose to get into muscles for energy. Examples include: white bread, white rice, sugar-sweetened cereals, fruit juices, gummy candies, sports drinks, and soda, she says. 

A quick general refresher on carbohydrates: They’re one of the three macronutrients. We think of carbs as a part of grains, but they’re also found in fruits, vegetables (both starchy and non starchy), dairy, and legumes, as well as snack foods, desserts, and sugar-sweetened drinks.

“Carbohydrates are the body’s primary source of energy,” explains Kirbie Daily, RDN, a sports dietitian for the University of Memphis Athletics. “When you eat carbohydrates, they are broken down into glucose in the body. The body either uses them right away for quick energy or they’re stored in muscles or the liver as glycogen to be used later.”

In addition to fast-digesting carbs, there are also slow-digesting carbs, which are often called complex carbohydrates. “While carbohydrates are the fastest digesting macronutrient, these are higher-fiber carbohydrates that will be the slower-digesting of the carbohydrates,” says Amy Goodson, RD, a sports dietitian in the Dallas-Fort Worth area.

It’s because of their fiber content (a nutrient that’s not absorbed) that these foods release energy more gradually. Slow-digesting carbs include whole grains like quinoa, oats, brown rice, beans, and non-starchy veggies like broccoli and kale.

When Might You Want to Eat Fast-Digesting Carbs?

There are three distinct times that athletes benefit from eating fast-digesting carbs: 

  • Before exercise to fuel up

  • During exercise to refuel

  • Post-exercise to recover

Most of the time, we’re encouraged to choose more complex (or slow-digesting) carbohydrates because these generally contain more nutrients like fiber. Only a small percentage of adults in the US are getting the recommended amount of fiber per day (14 grams of fiber per 1,000 calories you eat). Filling your diet with foods that provide these complex carbs—like whole grains and vegetables—will get you to your fiber goals. (Fiber benefits our digestive and heart health, aids in weight management, keeps our gut microbiome balanced, and more.) 

However, in certain circumstances, fast-digesting carbs can make a big difference:

Before Exercise

Fast-digesting carbs are going to give you a burst of get-up-and-go. “Fast-digesting carbs cause a quick rise in blood sugar, making them ideal when energy is needed immediately,” Baumann says. This can be especially helpful right before long and intense workouts, as they’ll zip energy to muscles rather quickly, she explains.

During Exercise

You’ll only need to fuel up with these carbs if you’re planning on doing long-duration exercise. Daily recommends replenishing with fast-digesting carbohydrates after every hour that you’re doing physical activity. For example, if you’re going on a long training run, you might eat every three to four miles. Don’t forget to stay adequately hydrated throughout the activity, which will help prevent digestive upset, she says.

Post-Exercise

“This is where more people can benefit from simple carbs,” Goodson says. “Ninety percent of the carbohydrates you consume after a workout of any kind goes to replenish glycogen stores.”

However, your body needs more than simple carbs in recovery. Goodson advises eating 15–25 grams of protein with those carbs, which will start the muscle-repair process. Some examples that combine a simple carb with protein include chocolate milk, honey in a protein smoothie, a peanut butter and jelly sandwich, or a Greek yogurt parfait with berries and honey. 

Tips for Choosing Fast-Digesting Carbs for Your Workout 

As beneficial as fast-digesting carbohydrates can be, you don’t always need one before, during, or after a workout. Follow these tips for learning about when and how to eat them to make them work for you:

Consider Your Meals

Goodson recommends eating a meal two to four hours before exercise. This is a good buffer timing-wise, as it allows you to get the nutrients you need with ample opportunity to digest them so you feel good when moving. Choosing complex carbohydrates at this time is a good idea, as their slower digestion will help give you lasting energy to get through your workout. 

Sometimes, you might also choose to eat a fast-digesting carb right before exercise (more on that in a second). But in many instances, you won’t need one, especially if you’ve been eating throughout the day. 

Assess Your Workout

Whether or not you “need” pre-workout fuel from a fast-digesting carb depends on the duration and intensity of the workout ahead of you, according to Goodson. “The bigger demand from exercise, the bigger demand of energy, which is why there are different recommendations based on your workout,” she says. Higher-intensity or longer-duration exercise requires more carbohydrates as a source of fuel. 

Here’s what that looks like in real life:

  • Speed walking in your neighborhood? Taking a 45-minute power yoga class? You probably don’t need a fast-digesting carb prior to exercise. “Having a fast-digesting carb won’t hurt you, but you probably don’t need it if you’re well-fueled before starting,” Goodson says. 

  • Doing a long and intense workout class or training session? Playing soccer for three hours? Going on a long run in marathon training? Then a simple carb may be your friend. “Whenever I’m counseling athletes, I suggest a fast-digesting carbohydrate if they’re partaking in physical activity that’s an hour or longer, since glucose stores will be used up after an hour,” Daily says. “That’s when it will be helpful to top off energy stores to power through the workout.”

Think About Breakfast

Early morning exerciser? You probably won’t be waking up at 4 AM just to eat a full meal before going to the gym at 6 AM. That’s where fast-digesting carbs can help.

“Simple carbs can be your friend for a little burst of energy to get going in your training session,” Goodson says. Duration and intensity also factor into what you eat. If you’re going for a 30-minute treadmill run, stick to a fast-digesting carb only (a banana or granola bar, for example). If it’s a 90-minute workout, then add protein to the mix to stabilize your blood sugar and avoid crashing mid-workout (like a protein bar or peanut butter on that banana).

Time It Right 

If appropriate for the exercise ahead, follow Daily’s 30-60 rule: Eat 30–60 grams of carbohydrates 30–60 minutes before activity. 

Hydrate Well

Make sure you’re sipping strategically. “Hydrate both right before, during, and after your workout,” Daily says. “As you sweat, you lose fluids and electrolytes, so you want to make sure to properly hydrate to avoid any cramping.”

Experiment 

What feels good in terms of portion size, food, and timing will depend on your body. So consider all of the above guidelines as you experiment with consuming carbohydrates for workouts. See what helps give you the energy needed to get through a workout without dragging, and adjust as necessary.

“Everyone’s tolerance for what they can eat and when will be different because nutrition is so individualized,” Daily says.

10 Examples of Fast-Digesting Carbs

These aren’t the only foods you can eat, of course, but these 10 fast-digesting carbs are sports dietitian-approved.

  • Honey: Yes, honey is helpful before a workout. “If a workout is starting in five to 10 minutes and you’re in a pinch, I like to recommend a spoonful of honey,” Daily says. “It will be absorbed super quick to provide energy without making you feel weighed down.”

  • A piece of fruit: Go for a banana, apple slices, or an orange, Daily suggests. They will have some fiber in them, but they also contain a large percentage of water for hydration, plus a range of electrolytes to support muscle function.

  • A sports drink: Sugary liquids, such as sports drinks, are easy to hydrate with before or during exercise. Go for the sports drink that contains sugar, rather than a sugar-free version. “The point of a sports drink is to have simple sugars for energy,” Goodson says. 

  • Cheerios: “A lot of my athletes love using Cheerios as a pre-workout,” Daily says. Although they’re made with whole-grain oats and contain some fiber, they tend to be digestive-friendly. Bonus: They’re mess-free and easy to toss in a bag. 

  • Apple sauce: A pouch of applesauce isn’t just convenient and gym bag-packable. It also has less than 1 gram of fiber, making it an easy-on-your-stomach choice. While you’ll get natural sugars and water from the apples themselves, some varieties are also sweetened, which will provide a nice bonus of simple carbs. 

  • Energy chew or gel: Chews and gels are great mid-workout fuel because they’re transportable and they also have additional ingredients like sodium (an electrolyte) and/or caffeine that can provide extra fuel and energy. Daily likes these for longer runs. 

  • Granola bar: If you’ve ever looked at the added sugar content of a small granola bar, you might be surprised. In this case, it’s a positive. Choose a variety that has minimal fiber and is small in size to get the fast-digesting carbs you’re looking for. 

  • A handful of pretzels: Regular pretzels (rather than those made with whole wheat or ancient grains) have simple carbs, plus they’re covered in salt for extra electrolytes.

  • Toast and jam: A slice of white toast topped with your favorite jelly or jam is a double-hit of fast-digesting carbs. Normally, you’d want to choose whole-grain toast, but as a fast-digesting carb, you’re better off looking for types of bread that are low in fiber, such as traditional white.

  • Crackers: Similar to pretzels, crackers are often made with refined white flour that can be beneficial when eaten prior to a workout. They have sodium and can be topped with a bit of jam if you’d like.

The Takeaway

Fast-digesting carbohydrates are simple carbohydrates that are lower in fiber so they break down easily in the body, allowing glucose to enter the bloodstream and go into muscle cells for energy. When eaten appropriately before, during, or after exercise, fast-digesting carbs can be a boon for your workout. “They’re not meant to be a staple at every meal,” Baumann says. “Overconsumption without exercise can cause blood sugar spikes and crashes, so finding the right balance is key.” 

Keep in mind that deciding whether or not to eat a fast-digesting carb around a workout depends on a host of factors. “Recommendations are not one-size-fits-all,” Goodson says. “Not everyone needs to have something before.”  Although most people, in general, won’t need to eat fast-digesting carbohydrates, they could be helpful if you’re exercising first thing in the morning or doing a long or especially intense exercise. 

For more guidance that applies directly to you, connect with a sports dietitian. 

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This content is for informational and educational purposes only and does not constitute individualized advice. It is not intended to replace professional medical evaluation, diagnosis, or treatment. Seek the advice of your physician for questions you may have regarding your health or a medical condition. If you are having a medical emergency, call your physician or 911 immediately.

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