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Evidence-Based Article
Intermittent Fasting
~ The Key to Peak Performance ~
Navigating the world of dieting can be intense and confusing, but even more so as an athlete. As an athlete, peak performance is the top priority. Achieving this is often a matter of balancing caloric intake, hydration, and macro nutrients, but within the past decade more athletes have been drawn to a nutritional regimen known as intermittent fasting. But what is intermittent fasting, or IFast, and how does it influence peak performance? Let’s take a look at the science to understand the effects of IFast on athletic performance.
What is Intermittent Fasting?
The broad definition of intermittent fasting is a long period of abstinence from food and or fluid consumption followed by a shorter period in which food and fluid consumption is permitted. The idea behind IFast has been around for centuries and often tied to religious practices but its recent, widespread use has been tied to the health claims of weight loss, lower blood pressure, and reduced risk for metabolic diseases such as Type 2 diabetes. One of the underlying mechanisms is that by extending the daily fasting duration, free fatty acids (FFA) are mobilized which increases fat oxidation and increases the production of ketones.
There are several forms of intermittent fasting with a wide range of definitions for time-restricted eating periods and fasting periods. The most common form of IFast is the 16/8 approach, which consists of 16 hours of fasting and an 8-hour period of caloric intake, or eating window. The typical 16/8 approach does not limit the consumption of fluids to the 8-hour eating window; however, some approaches, like those practiced during the Muslim month of Ramadan, restrict fluid consumption outside of the designated eating window.
How does IFast impact Athletic Performance?
Given the renewed interest in intermittent fasting, several studies have been conducted to assess the impact of different fasting methods and forms on overall peak athletic performance. However, the definition of IFast varies from study to study, making it difficult to determine the benefits, if any, of fasting as an athlete.
One review summarized the findings of several other studies and broke down their findings by exercise type. High intensity exercise, endurance sports, and resistance training were included as the categories for discussion. The overall findings determined that athletes participating in high intensity exercises experienced a dip in performance that lasted from a few days to a few weeks. Endurance athletes experienced a marginal decrease in performance or no effect at all depending on the fasting method that was being studied. Resistance athletes saw no negative effect to muscle mass gained or maintained but saw a decrease in fat mass.
Overall, more consistency between studies is needed to fully assess the impact of fasting on athletic performance. Many of the contradictory outcomes can be explained by the variations in the forms of fasting studied. While evidence suggests negative to no effect on performance, it is because of this variance that the overall impact remains inconclusive.
However, some studies suggest that intermittent fasting may help athletes reduce body weight without compromising their performance levels. This could be particularly beneficial for athletes who need to meet specific weight classes for sports like wrestling, martial arts, and boxing. In these cases, intermittent fasting may serve as an effective strategy for weight management while maintaining athletic performance.
If you are interested in trying intermittent fasting, it’s essential to discuss your plans with a provider or nutritionist and closely monitor how your body responds to these dietary changes, as there is no “one-size-fits-all” approach to achieving your health and nutritional goals.
< Recommendation by Our Experts>
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- Consult a Sports Nutritionist: Before starting intermittent fasting, it’s important to consult a qualified sports nutritionist. They can provide personalized advice tailored to your specific training needs and performance goals.
- Monitor Performance and Body Metrics: Regularly track your performance levels and body metrics, such as weight and energy, to evaluate how intermittent fasting affects you. This will help you make informed adjustments to your regimen as needed.
- Choose an Appropriate Fasting Protocol: Select a fasting protocol that best suits your sport and training schedule. Tailoring your approach will help you achieve optimal results while maintaining peak athletic performance.
< Reference >
- Hatori M, Vollmers C, Zarrinpar A, et al. Time-Restricted Feeding without Reducing Caloric Intake Prevents Metabolic Diseases in Mice Fed a High-Fat Diet. Cell Metabolism. 2012;15(6):848-860. doi:10.1016/j.cmet.2012.04.019
- Rynders CA, Thomas EA, Zaman A, Pan Z, Catenacci VA, Melanson EL. Effectiveness of Intermittent Fasting and Time-Restricted Feeding Compared to Continuous Energy Restriction for Weight Loss. Nutrients. 2019;11(10):2442. doi:10.3390/nu11102442
- Levy E, Chu T. Intermittent Fasting and Its Effects on Athletic Performance: A Review. Current Sports Medicine Reports. 2019;18(7):266-269. doi:10.1249/JSR.0000000000000614