Are you a morning workout person? Have you debated eating breakfast before your morning workout?
When you exercise before breakfast, your body is in a fasted state since you haven't eaten anything since dinner or an evening snack. This is referred to as night-fasted.
In this post, we'll go over some of the benefits of working out while night-fasted and some of the downsides.
Benefits
More Fat-Burning
There has been some research showing that you burn more fat when you workout in a night-fasted state. During high-intensity exercise, you burn carbohydrates, usually from previous meals (half an hour to 3 hours before) or stored in the body.
Fat is mostly used as an energy source during lower intensity exercise. But when you're in a night-fasted state, fat is more readily used to fuel your workout! Since you haven't eaten your body relies on what it has stored. Some studies even showed that exercising after eating inhibited fat burning!
Improves Digestion
If you've ever exercised shortly after eating you know the struggle! Stomach cramps, indigestion and acid reflux are just some of the not-so-fun effects of working out after eating. In the morning, it can be a struggle to fit in enough time for breakfast to digest and to complete a good workout. Exercising before eating may be the solution! A post by Rita Colorito quotes physicians who recommend working out on an empty stomach to reduce reflux because the stomach will be empty.
Downsides
Potential “Bonking”
Your body's main source of fuel is glucose (sugars!) which is stored in muscles as glycogen. During a workout, glycogen is broken down into glucose molecules that can be used as energy! Without access to sufficient carbs, there is potential you "bonk" (sudden fatigue/loss of energy) when your brain can no longer get enough glucose for fuel. Eating foods high in carbs will help you recover from this!
Difficult for Endurance
Due to the previous point, it can make it more difficult to perform endurance exercise such as running long distances. In a review by Aird et al. (2018), they discovered that people's endurance exercise performance was also worse when not fed compared to having eaten before working out. But this doesn't mean that endurance exercise on an empty stomach is impossible! Carrying some quick, easily digestible and high-carb snacks can help prevent bonking and increase performance!
Resources
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
Murray, B., & Rosenbloom, C. (2018). Fundamentals of glycogen metabolism for coaches and athletes. Nutrition Reviews, 76(4), 243–259. https://doi.org/10.1093/nutrit/nuy001
Sassi, K. (2018, June 26). Exercise-Induced GERD: What to Do About It | Everyday Health. EverydayHealth.Com. https://www.everydayhealth.com/gerd/best-exercises-to-beat-heartburn.aspx
The science of “hitting the wall.” (2017, May 2). EurekAlert! https://www.eurekalert.org/pub_releases/2017-05/cp-tso042717.php
Wallis, G. A., & Gonzalez, J. T. (2018). Is exercise best served on an empty stomach? Proceedings of the Nutrition Society, 78(1), 110–117. https://doi.org/10.1017/s0029665118002574
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