By Laci Stautzenberger, TX State Nutrition Intern
Why are people eating gummy bears at the gym, and what in the world are run gels? More casual joggers and weightlifters are shifting gears and entering the space of strength gains, muscle gains and cardiovascular gains. Overall, optimizing results and enhancing effectiveness and payoff. What does eating during your workout have to do with optimized performance? Should you eat during your workout, and if so, what?
How the Body Uses Carbohydrates
During exercise, carbohydrates (CHOs) are the body’s primary source of fuel. Muscle glycogen is the storage form of carbohydrates within muscle tissue. For weightlifting, we use stored CHOs in the form of muscle glycogen for energy in short bursts. Conversely, when running we use muscle glycogen as energy in a slow, gradual manner. Other sports, such as football, boxing, soccer, biking, etc., use stored glycogen in a combination of these two ways. CHO intake improves muscle glycogen resynthesis, maintains blood glucose levels, increases insulin, and decreases cortisol. This CHO domino effect is not only glycogen sparing but also protein sparing. In other words, CHOs stop your body from using muscle protein for energy. When nearing carbohydrate depletion, intra- workout CHOs help your body shift from a state of catabolism or muscle protein breakdown to anabolism.
Who Benefits from Intra-Workout CHOs
Research shows that pre- and post- workout carbohydrates support muscle glycogen conservation, but the literature surrounding intra-workout nutrition isn’t as clear. The need to replenish glycogen mid- workout depends on how depleted we become during the workout. This means that session intensity and duration are important considerations when deciding to incorporate CHOs into a workout session.
Evidence demonstrates that intra-workout carbohydrates may be useful for sessions (running, boxing, soccer, endurance sports, etc.) lasting longer than 60 minutes, sessions including 10 or more sets per muscle group (weightlifting, CrossFit, etc.), or multiple sessions a day. If your training does not meet one or more of these, intra- workout carbohydrate supplementation will likely be of no additional benefit to proper pre- and post- workout nutrition. If this is your type of exercise, then intra- workout CHOs may be a great addition. Glycogen maintenance, blood glucose stability, and cortisol maintenance resulting from intra- CHO intake, opens the door to more sets and reps per session, increased endurance, and delayed fatigue.
CHO Amount and Sources
30-60 grams per hour is the general recommendation for intra-workout CHO intake, but this can change depending on total session length. What are good sources? Sadly, my first recommendation isn’t gummy bears. However, I do think they are great to occasionally add variety to your routine. Many athletes use sports drinks like Gatorade and run gels or chews for quick carbs like sucrose, glucose, and fructose, but whole food sources have proven equally effective and provide additional benefits like vitamins, minerals, and antioxidants. An optimal sources of intra-workout carbohydrates include multiple transportable carbohydrates (MTCs). MTCs are a mixture of simple sugars like glucose and fructose or maltodextrin and cyclic dextrin that are absorbed steadily and efficiently during exercise. Foods like bananas, dates, unsweetened apple sauce, blueberries, raisins, grapes, and honey are great sources of MTCs.
It is best to start with a liquid carbohydrate solution due to fiber and other nutrients found in some MTC sources. A 6% solution is optimal for carbohydrate utilization and is a great way to ease into the world of mid session consumption. Liquid carbohydrates can be easiest on digestion during exercise. You can make your own by combining 6 grams of carbs from honey (1 Teaspoon), for every 100ml of water (16oz is recommended, so roughly 4.5 teaspoons of honey). Maltodextrin or cyclic dextrin drinks can also be a great way to supplement carbohydrates. Maltodextrin is generally recommended for post-workout nutrition because it is absorbed very quickly, while a highly branched cyclic dextrin source can provide slow, steady energy. Maltodextrin drinks can also be combined with foods like honey or applesauce to increase carbohydrate concentration and keep digestion smooth.
Personalizing your Protocol
When introducing carbohydrates to your routine, remember not to try out new protocols on competition day. Digestion is individual, so trialing carbohydrate sources during practice sessions will ensure you choose a source that your body responds well to during important sessions. This is also the time to play with carbohydrate amounts; you may not digest or perform well under current CHO intake recommendations, so adjust the amounts over time as needed .
Sources
Bird, Stephen P et al. “Supplementation Strategies for Strength and Power Athletes: Carbohydrate, Protein, and Amino Acid Ingestion.” Nutrients vol. 16,12 1886. 14 Jun. 2024, doi:10.3390/nu16121886
Cribb, Paul J, and Alan Hayes. “Effects of supplement timing and resistance exercise on skeletal muscle hypertrophy.” Medicine and science in sports and exercise vol. 38,11 (2006): 1918-25. doi:10.1249/01.mss.0000233790.08788.3e
Henselmans, Menno et al. “The Effect of Carbohydrate Intake on Strength and Resistance Training Performance: A Systematic Review.” Nutrients vol. 14,4 856. 18 Feb. 2022, doi:10.3390/nu14040856
Naderi, Alireza et al. “Carbohydrates and Endurance Exercise: A Narrative Review of a Food First Approach.” Nutrients vol. 15,6 1367. 11 Mar. 2023, doi:10.3390/nu15061367
