Carbs Before or After Workout? Why You Need Both

Ever since low-carb diets exploded onto the weight-loss scene, carbohydrates have been targeted as a dietary evil. “Experts” have led us to believe that cutting back on carbs is necessary to achieve weight loss and muscle mass. But here's the truth: we all need carbohydrates in our diets, every single day. Period.

In two of our other blog posts — How Much Protein Do I Really Need? and Protein Myths Busted — we tackled the often-controversial question of just how much protein you need before and after a workout. Here, we give you the truth about carbohydrates. This includes how much you need and how they can promote performance and recovery.

Benefits of Carbs for Pre-Exercise Nutrition

Whether you're working out to gain muscle mass, lose fat, or for better performance, to achieve your goal you need sustained energy. One of two things happens when you run out of steam in the middle of a workout:

• You stop early and don't train for as long as you had planned.

• You finish your workout but hold back and don't push as hard.

In either case, running out of energy means a compromised workout. One method of sustaining energy throughout a workout is by maximizing glycogen storage.

Glycogen is the stored sugar in your liver. It is released when you need more energy. So, if you don't have enough stored up, your workout will go south quickly. Guess what gives you that perfect glycogen build-up before a workout? Carbohydrates.

But wait. Doesn’t this contradict the benefits of fasted exercise? Yes but no. Not eating before exercise does offer metabolic advantages. However, as one review confirms, if the goal is improved performance, eating before exercise helps create this effect. (1)

There are many different methods for maximizing glycogen storage. Besides carbohydrates, high-fat diets have been proven to increase endurance as well. For today, we will focus on how carbohydrates can maximize glycogen storage.

The Importance of Post-Workout Carbs

Guess what is also important after a workout? You got it: carbohydrates.

After a training session, glycogen needs to be replenished. It’s like filling up your car after running errands. The fuel is needed to keep it going or you risk hitting empty and being stranded on the side of the road.

There are other benefits of replenishing glycogen after a workout. If you don’t, you could experience muscle breakdown and slow muscle recovery. This can make building muscle more difficult. You may notice diminished performance too.

One study suggests that carb intake is even more important for athletes with limited recovery time between training sessions. (2) When exercise is closely spaced, carbs should be prioritized. Consuming them post-workout helps improve the rate of muscle glycogen resynthesis.

What Research Says About Timing Carbs Before or After Workout

To build up enough glycogen ahead of a workout for sustained energy, you need to get the timing right. Here's what the research says about carbohydrate intake as part of a pre-workout meal:

• A 2020 review proposes that carbs be consumed within four hours of exercise. Whether they are eaten 15 or 60 minutes before the workout session doesn’t seem to change the effects. (3)

• Another study found similar results. It noted that subjects’ performance improved when carbs were consumed between 30 minutes and four hours before exercise. (4)

Some studies have also looked at the best approach for carbs in post-workout meals. Here’s what they’ve found:

• A 2021 review indicates that eating carbs within two hours of exercise aids in recovery. (5)

• An article in Nutrients adds that consuming carbs within 30 minutes of a workout can increase muscle glycogen resynthesis rates by 40%. (6)

What’s the takeaway? Aim to consume carbs within four hours before a workout and again 30 minutes to two hours after. This will help give you enough energy to complete an effective workout while also supporting muscle recovery.

Choosing the Right Carbs: Complex Carbs vs. Simple Carbs

There are two basic types of carbohydrates: simple and complex. What’s the difference?

Simple carbohydrates are sugars. Glucose, fructose (fruit sugar), and sucrose (table sugar) are all simple carbs. This carbohydrate type provides the fastest source of available energy. Think of the kid who starts bouncing off the walls after eating candy or drinking soda.

Complex carbohydrates are found in plant-based foods. This includes whole grains and starchy vegetables such as potatoes. A complex carbohydrate provides sustained energy over longer periods of time. It also helps replenish glycogen after training. 

For quick recovery of glycogen stores, simple carbs are the preferred source of energy post-workout. They can also provide quick bursts of energy when you're flagging during exercise.

Complex carbs are your best choice for sustained energy two to three hours before a workout. They’re also a good choice for the post-workout recharge. And they can be combined with simple carbohydrates for a quick fix.

Keep in mind that a simple carbohydrate has a greater effect on blood sugar. It can cause a person’s blood sugar level to rise quickly. Therefore, people with diabetes may want to monitor their levels to ensure that they remain in the safe range.

Determining Carbohydrate Intake Pre- and Post-Workout

Exactly what portion size you need depends on many factors. They include your current weight, your goals, and the purpose of a training session.

If your goal is to get through a cardiovascular endurance workout, for example, you need more glycogen build-up in advance. But if you’re strength training to build muscle mass, you don't need quite as much in your glycogen storehouse. Likewise, for post-workout carb intake, you need more to replenish after a long endurance workout than after a strength training session.

A general rule of thumb is to experiment with your body. Start by consuming between 0.5 and 1.0 grams of carbs per kilogram of body weight before and after workouts. Increase this amount for endurance and reduce it for resistance exercise.

For endurance athletes, the recommended pre-workout intake of carbs is:

• 60 grams per hour for workouts lasting two to three hours

• Up to 90 grams per hour for longer endurance events

• Less than 60 grams of carbs pre-workout for anything less than two hours

Combine Carbs and Protein for Optimal Effects

Protein is another important nutrient for muscle building and recovery. Should you eat proteins and carbs together? The answer is a definite yes. 

Carbohydrates and protein work together to provide:

• Sustained performance.

• Increased glycogen storage.

• Faster recovery times.

Consuming a carbohydrate and protein combination supports maximal muscle growth. If you have protein but not enough carbs, you may experience muscle breakdown. This can also lead to a loss of skeletal muscle mass. Carbohydrate and protein sources also work together for faster muscle recovery. This is especially important after a strength training workout.

Add about 0.5 grams of protein per kilogram of body weight to pre- and post-workout carbs. Lean protein sources are best. Whole-grain bread with nut butter is one option. A protein powder shake with fruit is another.

The Bottom Line

The bottom line is that eating carbs both pre- and post-workout provides many benefits. They help you sustain the energy needed for exercise. They also improve performance and aid in muscle recovery.

You can learn more about sports nutrition in ISSA’s Nutritionist Certification course. This course teaches you how to devise a meal plan for muscle gain, fat loss, and more. It also covers pre-workout nutrition and post-exercise eating in greater depth. This helps you provide clients with advice as to the best foods for their specific goals.

References

1. Aird, T. P., Davies, R. W., & Carson, B. P. (2018). Effects of fasted vs fed‐state exercise on performance and post‐exercise metabolism: A systematic review and meta‐analysis. Scandinavian Journal of Medicine & Science in Sports, 28(5), 1476–1493. https://doi.org/10.1111/sms.13054

2. Craven, J., Desbrow, B., Sabapathy, S., Bellinger, P., McCartney, D., & Irwin, C. (2021). The Effect of Consuming Carbohydrate With and Without Protein on the Rate of Muscle Glycogen Re-synthesis During Short-Term Post-exercise Recovery: a Systematic Review and Meta-analysis. Sports Medicine - Open, 7(1). https://doi.org/10.1186/s40798-020-00297-0

3. Rothschild, J. A., Kilding, A. E., & Plews, D. J. (2020). What Should I Eat before Exercise? Pre-Exercise Nutrition and the Response to Endurance Exercise: Current Prospective and Future Directions. Nutrients, 12(11), 3473. https://doi.org/10.3390/nu12113473

4. Burdon, C. A., Spronk, I., Cheng, H. L., & O’Connor, H. (2016). Effect of glycemic index of a pre-exercise meal on endurance exercise performance: a systematic review and meta-analysis. Sports Medicine, 47(6), 1087–1101. https://doi.org/10.1007/s40279-016-0632-8

5. Bonilla, D. A., Pérez-Idárraga, A., Odriozola-Martínez, A., & Kreider, R. B. (2020). The 4R’s Framework of Nutritional Strategies for Post-Exercise Recovery: A Review with Emphasis on New Generation of Carbohydrates. International Journal of Environmental Research and Public Health, 18(1), 103. https://doi.org/10.3390/ijerph18010103

6. Alghannam, A. F., Gonzalez, J. T., & Betts, J. A. (2018). Restoration of muscle glycogen and functional capacity: role of Post-Exercise carbohydrate and protein Co-Ingestion. Nutrients, 10(2), 253. https://doi.org/10.3390/nu10020253