Do amino acids break a fast? Here at aminoVITAL®, this is a question that we get asked frequently. It is no surprise either, considering that fasting and intermittent fasting are becoming increasingly popular among those looking to improve their health and fitness. With the benefits of fasting becoming more established, people who normally use BCAAs to prevent muscle breakdown and reduce muscle soreness are now wanting to know if those same amino acids are breaking their fast and diminishing their progress.
The short answer is yes, BCAAs do technically break a fast. However, not in a way that will reduce any of the potential health benefits of fasting.
At this point, you should be asking yourself what your reasons are for fasting. If you are fasting for religious or personal reasons and do not want to break the fast out of principle, then you should refrain from taking BCAAs or anything with caloric value. If you are fasting to restrict calories, burn fat, or for any other wellness reasons, then the pros of consuming BCAAs far outweigh any cons!
What Does It Mean To Break A Fast?
First, let’s discuss what it means when we say taking BCAAs technically breaks a fast, but not in a way that will hurt our efforts. To answer that, we need to address the following question, “How do you define breaking a fast?”
A fast is broken when we consume anything that has caloric value and causes an insulin response. You can think of insulin as the hormone that helps put all of the groceries away! It helps transfer the macronutrients from your meals to the appropriate places. Whenever we consume calories and mainly glucose (carbohydrate), we trigger a response from insulin that helps us transport those calories to the body’s cells for energy use (4). More broadly, this means switching from using predominantly fat as energy during our fasted state to using predominantly carbohydrate as energy when we trigger an insulin spike in a fed state.
Do BCAAs Trigger An Insulin Spike?
Okay, so we don’t want to trigger an insulin spike. Do BCAAs do that? No!
BCAAs do trigger a small insulin response, but it is not a spike by definition. And, it is not enough to switch your body out of the predominantly fat burning state. In fact, a study by Zhang et al. showed a modest insulin response to the ingestion of both 1g and 5g of BCAAs (7). Another study that looked at Leucine alone, again showed a modest response in insulin. In fact, the insulin response to Leucine was not much higher to that of water (5). “Leucine, when ingested alone, increased the serum insulin area response modestly (5).”
“Okay,” you may be thinking to yourself, “but why even take BCAAs in the first place?” That is an excellent question and one we will now address!
BCAAs help reduce fatigue, both peripheral and central.
Fatigue is one of the hardest barriers to overcome while fasting, especially if you engage in any type of fasted exercise or a prolonged fast.
Peripheral fatigue occurs in the muscles when there is a limited supply of glycogen or glucose stored in the muscle & liver (6). If you are exercising in a fasted state, then your glycogen stores will be low. And, you are going to feel peripheral fatigue set in more quickly, than if you had recently replenished those stores. BCAAs can help reduce this effect and can increase exercise capacity, or time to exhaustion, specifically when muscle glycogen has been depleted (3).
Central Fatigue is systematic fatigue that results from physical and mental stress placed on the central nervous system. Again, BCAAs can help mitigate these effects by competing with tryptophan, a precursor to serotonin, which contributes to central fatigue (1).This is a huge benefit to those in a fasted state because they are already putting their body in a stressed state by withholding food. BCAAs can help mitigate some of the central fatigue that comes with fasting and fasted exercise.
BCAAs can help reduce muscle soreness and keep you performing at your best.
A study conducted at East Tennessee State University showed that collegiate distance runners felt less soreness in their legs when supplementing with aminoVITAL® vs. placebo (2). Our specific formulas use BCAAs along with other active ingredients to help reduce muscle soreness and protect against muscle damage.
Why should you care about any of this? Well, less fatigue and less soreness are going to lead to more productive training sessions. If you can perform and train just as hard as you did the day before, your progress will come much quicker. All the benefits of BCAAs are also going to make being in a fasted state much more enjoyable and, therefore, you are going to be more likely to stick with it. It is much easier to continually work out in a fasted state if you are able to perform at your best, continually hit personal records, or not feel as worn down by the fatigue that normally comes with fasting.
- BLOMSTRAND, E. (2006). A ROLE FOR BRANCHED-CHAIN AMINO ACIDS IN REDUCING CENTRAL FATIGUE. THE JOURNAL OF NUTRITION,136(2), 544-547. DOI:10.1093/JN/136.2.544S
- FLYNN, A., WHITON, T., & SATO, K. (2018). BRANCHED-CHAIN AMINO ACID SUPPLEMENTATION MAY PRODUCE MARGINAL REDUCTIONS IN MUSCULAR SORENESS IN COLLEGIATEDISTANCE RUNNERS. MEDICINE & SCIENCE IN SPORTS & EXERCISE,50, 588. DOI:10.1249/01.MSS.0000537026.73026.53
- GUALANO, A. B., BOZZA, T., LOPEZ DE CAMPOS, P., ROSCHEL, H., DOS SANTOS COSTA, A., LUIZ MARQUEZI, M., & HERBERT LANCHA, A., JR. (2011). BRANCHED CHAIN AMINO ACIDS SUPPLEMENTATION ENHANCE EXERCISE CAPACITY AND LIPID OXIDATION DURING ENDURANCE EXERCISE AFTER MUSCLE GLYCOGEN DEPLETION. THE JOURNAL OF SPORTS MEDICINE AND PHYSICAL FITNESS,51, 82-88. RETRIEVED June 18, 2019
- Insulin. (n.d.). Retrieved June 18, 2019, from http://www.yourhormones.info/hormones/insulin/
- Kalogeropoulou, D., Lafave, L., Schweim, K., Gannon, M. C., & Nuttall, F. Q. (2008). Leucine, when ingested with glucose, synergistically stimulates insulin secretion and lowers blood glucose. Metabolism, 57(12), 1747-1752. doi:10.1016/j.metabol.2008.09.001
- NEWSHOLME, E. A., & BLOMSTRAND, E. (2006). BRANCHED-CHAIN AMINO ACIDS AND CENTRAL FATIGUE. THE JOURNAL OF NUTRITION,136(1), 274-276. DOI:10.1093/JN/136.1.274S
- Zhang, Y., Kobayashi, H., Mawatari, K., Sato, J., Bajotto, G., Kitaura, Y., & Shimomura, Y. (2011). Effects of Branched-Chain Amino Acid Supplementation on Plasma Concentrations of Free Amino Acids, Insulin, and Energy Substrates in Young Men. Journal of Nutritional Science and Vitaminology,57(1), 114-117. doi:10.3177/jnsv.57.114