Many athletes fuel up before a workout to boost energy and enhance performance. Experts often advocate for carb-rich meals, citing their ability to provide energy and replenish muscle glycogen. Is that truly how it works? Do you really need carbs before training?
Dr. Mike Israetel and Dr. Jake Remmert, a researcher at Florida Atlantic University’s Muscle Lab, recently explored the topic of carbs before training; drawing from scientific studies and personal experience, they shared their insights on the benefits of pre-workout carbs.
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Importance of Carbs Before Training
Pre-workout carbohydrates can curb hunger, enhance performance, and improve focus during training. While Dr. Israetel acknowledges ongoing debates within sports nutrition over the role of eating before workouts, he highlights three notable considerations:
- Glycogen — Muscles primarily rely on glycogen stores (i.e., energy reserves built from the food consumed the day before) to fuel performance.
- Blood Glucose — consuming carbs in a pre-workout meal can elevate blood glucose levels, providing an immediate energy boost. “We know that under certain circumstances, blood glucose was pulled in for energy for cells even while they’re contracting like a muscle. So maybe it’s in that benefit to eat carbs,” Dr. Israetel explained.
- Hunger Control — Even with fully replenished glycogen levels, training on an empty stomach can trigger the body’s hunger mechanisms if no food has been consumed earlier in the day, negatively affecting lifting performance.
Studies on Carbs Pre-Workout
Dr. Remmert referenced three consecutive studies conducted with the same group in 2019, 2020, and 2021. These studies followed a consistent design: participants consumed a pre-workout meal before completing four sets of squats and four sets of bench presses. The researchers then measured the total number of reps performed across all sets.
Study 1
The first study compared the effects of a standardized carb-rich breakfast to only drinking water. (1) On average, participants who ate breakfast performed better, completing more repetitions across all sets.
Study 2
The following year, the same subjects returned and consumed a similar high-carb breakfast with water. This time, they also had a placebo meal — calorie-free but designed to match the texture and volume of the real meal.
The high-carb and placebo meals outperformed water in terms of performance, with no significant difference in training output. (2) Remmert speculated that the benefit wasn’t solely due to the carbohydrates; there had to be another factor at play.
Study 3
The third study followed a similar methodology. Participants consumed either a semi-solid oatmeal or a liquid meal containing the same amount of carbs. The results showed that the semi-solid meal outperformed the liquid one, likely due to providing greater satiety. (3)
Dr. Remmert referenced a meta-analysis on pre-workout carbs that found consuming carbs was beneficial, on average, particularly for longer and more intense workouts. (4) However, researchers could not pinpoint exactly why this happened. Remmert speculated it might be as simple as avoiding hunger or distraction during training.
Dr. Israetel concurred, noting that carbohydrates significantly support endurance and performance during extended, demanding exercises. Feeling comfortably full could boost energy levels and improve focus, enabling more productive workouts.
Ultimately, eating before exercising is likely more beneficial, as training on an empty stomach often leads to discomfort and reduced performance. Solid food is more advantageous than liquid calories “because if you’re just drinking Gatorade, that doesn’t exactly zap your hunger,” Dr. Israetel said. “It will provide carbohydrates, but maybe getting a banana or a sandwich a couple of hours before you lift is best practice.”
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References
- Bin Naharudin, M. N., Yusof, A., Shaw, H., Stockton, M., Clayton, D. J., & James, L. J. (2019). Breakfast Omission Reduces Subsequent Resistance Exercise Performance. Journal of strength and conditioning research, 33(7), 1766–1772. https://doi.org/10.1519/JSC.0000000000003054
- Naharudin, M. N., Adams, J., Richardson, H., Thomson, T., Oxinou, C., Marshall, C., Clayton, D. J., Mears, S. A., Yusof, A., Hulston, C. J., & James, L. J. (2020). Viscous placebo and carbohydrate breakfasts similarly decrease appetite and increase resistance exercise performance compared with a control breakfast in trained males. The British journal of nutrition, 1–9. Advance online publication. https://doi.org/10.1017/S0007114520001002
- Naharudin, M. N., Yusof, A., Clayton, D. J., & James, L. J. (2022). Starving Your Performance? Reduced Preexercise Hunger Increases Resistance Exercise Performance. International journal of sports physiology and performance, 17(3), 458–464. https://doi.org/10.1123/ijspp.2021-0166
- King, A., Helms, E., Zinn, C., & Jukic, I. (2022). The Ergogenic Effects of Acute Carbohydrate Feeding on Resistance Exercise Performance: A Systematic Review and Meta-analysis. Sports medicine (Auckland, N.Z.), 52(11), 2691–2712. https://doi.org/10.1007/s40279-022-01716-w
Featured image via Shutterstock/Ajan Alen
