Intermittent Fasting Benefits for Athletes Largely Hype According to a New Study Summary
- While many athletes sing praises about the intermittent fasting benefits for athletes, it’s essential to compare intermittent fasting effectiveness to the tried-and-true calorie-restricted diets.
- The study aimed to assess whether intermittent fasting (IF) diets are associated with improvement in weight loss, metabolic parameters, and subjective well-being in people with obesity.
- IF does not show a significant difference in weight loss compared to non-intermittent fasting diets. There was no difference in the efficacy between alternate-day fasting and time-restricted either. No differences in fasting plasma glucose, cholesterol, or blood pressure were found either.
- The hype around Intermittent Fasting as a superior weight loss method is just that – hype. While it might work for some, it’s not the magic bullet many believe it to be. It’s essential to choose a sustainable and individualized approach, whether it’s IF, calorie restriction, or another method
Introduction
The global obesity epidemic is a pressing health concern, with millions seeking effective weight loss solutions. Among the popular methods are Intermittent Fasting (IF) and Time-Restricted Eating. While the traditional calorie-restricted diet has been the go-to for many, numerous athletes have highlighted the intermittent fasting benefits for athletes in shedding fat and building muscle through incorporating resistance training, including maintaining lean body mass. However, there are concerns that intermittent fasting may not provide enough food or protein for athletes to adequately build muscle. Is IF and time-restricted dieting truly superior to the standard calorie-restricted diet? Let’s dive into the latest study.
The Rise of Intermittent Fasting Among Athletes
Intermittent Fasting, often hailed as a revolutionary weight loss method, involves cycles of eating and fasting. The rise of intermittent fasting among elite athletes has been fueled by claims of enhanced fat burning and high energy reserves. Intermittent fasting benefits for athletes have been suggested to occur through enhanced fat burning and high performance.
Fasting for more than 8-12 hours can enhance ketosis and lipolysis (i.e., fat burning) and reduce oxidative stress (i.e., cell damage). Oxidative stress has been linked to several chronic diseases, including cancer, heart disease, and Alzheimer’s disease. However, it’s important for athletes to consume enough energy and nutrients during their eating window to properly support their performance and have a successful workout.
There are several IF methods, each with potential intermittent fasting benefits for athletes, such as Periodic Fasting (PF), Alternate Day Fasting (ADF), or Time-Restricted Eating (TRE). (de Cabo & Mattson, 2019) Athletes are attracted to intermittent fasting’s potential benefits, such as fat loss, muscle preservation, and metabolic flexibility. The rise of intermittent fasting in sports may be influenced by social media, celebrity endorsements, and anecdotal success stories. However, the scientific research on intermittent fasting benefits for athletes is still limited and inconclusive. There are many forms of IF, here is a definition of the few types:
IF: Intermittent fasting (IF)
Intermittent fasting (IF) involves alternating periods of eating and fasting, typically within a day. The most common types of intermittent fasting include alternate-day fasting, time-restricted eating, and periodic fasting. IF can impact energy intake, hormone secretion, body composition, and athletic performance. Athletes should consider their training schedule, energy needs, muscle mass goals, and performance requirements when implementing intermittent fasting.
Time-Restricted Eating (TRE),
Time-restricted eating (TRE) involves limiting food intake to a specific window of time each day. While a recent study found that TRE did not improve athletic performance in trained cyclists, other studies have shown potential benefits for weight loss and metabolic health.
Periodic Fasting (PF)
Periodic fasting, which involves longer fasting periods lasting 24 hours or more, is practiced intermittently by some athletes for potential performance benefits, weight control goals, or religious reasons. This type of fasting can impact various aspects including low glycogen reserves, fat mass, hormone secretion, muscle soreness, and exercise performance. Athletes considering periodic fasting should carefully plan their fasting schedule, food intake, and training session timing. Monitoring training adaptations, energy levels, muscle power, and overall well-being is crucial during days of intermittent fasting as an athlete.
Are Intermittent Fasting Benefits for Athletes Backed by Science?
While many athletes sing praises about the intermittent fasting benefits for athletes, it’s essential to compare IF’s effectiveness to the tried-and-true calorie-restricted diets. Calorie restriction means consuming fewer calories than expended. It’s a straightforward approach backed by science and has been a cornerstone of weight loss strategies for decades.
Calorie restriction involves a gradual reduction in calories, ensuring that athletes are still consuming enough calories and nutrients to fuel their bodies for training and maintain a healthy heart rate. Most diets increase or maintain protein while reducing fats and/or carbohydrates. Recent research suggests that intermittent fasting benefits for athletes may not be superior to that of traditional calorie restriction.
The Science Behind Intermittent Fasting for Athletes
The effects of intermittent fasting on athletic performance are multifaceted, encompassing metabolic, hormonal, and cellular adaptations. It has the potential to influence protein synthesis, muscle mass, glycogen utilization, endurance, and strength performance. Research indicates possible benefits of intermittent fasting for body composition, blood sugar control, and cardiovascular health. However, as contradictory results of several studies have shown, the practice of intermittent fasting may not always improve athletic performance.
Further studies are required to fully comprehend the long-term effects of intermittent fasting on athletic performance, recovery, and overall health outcomes. The impact of intermittent fasting on athletes can be observed through the natural participants of Ramadan, providing insights into the potential benefits and drawbacks of this practice for sporting performance. Athletes should prioritize food quality, adequate protein intake, energy requirements, and strategic training periodization in conjunction with the benefits of intermittent fasting practices.
Notably, some previous meta-analyses performed on a diverse population of overweight subjects with or without obesity showed greater efficacy of intermittent fasting in comparison with the standard control diets. (Cui et al., 2020; He et al., 2021; Pellegrini et al., 2020) However, these meta-analyses included trials on individuals who were not obese, who might have a different dietary response than those with obesity. (Cho et al., 2019; Liu et al., 2022)
Recent studies have delved into the intermittent fasting benefits for athletes, comparing IF’s impact on athletic performance, recovery, and overall health against other dietary strategies. The results might surprise many who have bought into the IF hype.
Notably, some previous meta-analyses performed on a diverse population of overweight subjects with or without obesity showed greater efficacy of intermittent fasting in comparison with the standard control diets. (Cui et al., 2020; He et al., 2021; Pellegrini et al., 2020) However, these meta-analyses included trials on individuals not affected by obesity, who might have a different dietary response than those with obesity. (Cho et al., 2019; Liu et al., 2022)
New The Meta-Analysis Study on IF vs. Calorie Restricted Diets (CR)
A systematic review and meta-analysis from “Nutrition, Metabolism & Cardiovascular Diseases (2023)” titled Effectiveness of intermittent fasting for weight loss in individuals with obesity: A meta-analysis of randomized controlled trials delved deep into this topic. The study rigorously analyzed various databases, including PubMed and Cochrane CENTRAL, and included randomized controlled trials comparing IF with CR diets.
The meta-analysis was conducted on randomized controlled trials longer than 2 months, comparing weight loss with IF diets and control diets in people with a Body Mass Index (BMI) > 30. The analysis included 9 trials with 273 participants on IF diets and 267 on continuous restricted diets. The trials were conducted in various countries, including the USA, Norway, Australia, China, and Brazil. The mean age of the participants was 44.7 years, and the proportion of male patients was 33%.
Results
The key takeaway? There’s no significant difference in weight loss between calorie-restricted diets and any form of IF. Furthermore, the groups had no differences in fasting plasma glucose, cholesterol, or blood pressure. With IF diets, a temporary reduction in LDL-Cholesterol was observed at 2-4 months, but this effect was not maintained in the longer term. This suggests that while there might be short-term benefits to LDL cholesterol levels with IF, these benefits do not persist in the long run.
There’s no significant difference in weight loss between calorie-restricted diets and any form of IF. Furthermore, the groups had no differences in fasting plasma glucose, cholesterol, or blood pressure.
Delving Deeper: Why IF Might Not Be Superior
While IF has metabolic and physiological effects, it doesn’t necessarily translate to superior weight loss. Factors like meal timing and calorie intake play crucial roles. (Templeman et al., 2020) Moreover, adherence to the diet, mood changes, and potential risks can impact its effectiveness. (Currenti et al., 2021)
Concerning psychological well-being, some patients on intermittent fasting reported transient mood improvement and decreased anger. (Hussin et al., 2013) The present meta-analysis doesn’t show any significant effect of IF compared to CR on obesity-associated cardiovascular risk factors, except for a short-term reduction in LDL. (Meng et al., 2020) Interestingly, intermittent fasting didn’t offer any long-term weight loss advantage.
The Broader Picture: Other Health Benefits and Concerns
Beyond weight, IF doesn’t show significant advantages in cholesterol, blood glucose, or blood pressure levels. While some report short-term mood improvements, the long-term mental health effects remain a topic of debate. However, IF may serve as an alternative to calorie restriction as it appears overall safe, even if no data on all-cause mortality, cardiovascular mortality, stroke, myocardial infarction, and heart failure are available for IF diets (Allaf et al., 2021) data on cardiovascular risk factors appear to be reassuring.
Conclusion
The intermittent fasting benefits for athletes have generated much discussion and excitement in the sports and fitness world. However, as with all trends, separating the hype from the reality is vital. While it might work for some, it’s not the magic bullet many believe it to be. Choosing a sustainable and individualized approach is essential, whether it’s IF, CR, or another method.
References
Allaf, M., Elghazaly, H., Mohamed, O. G., Fareen, M. F., Zaman, S., Salmasi, A. M., Tsilidis, K., & Dehghan, A. (2021). Intermittent fasting for the prevention of cardiovascular disease. Cochrane Database of Systematic Reviews(1). https://doi.org/10.1002/14651858.CD013496.pub2
Anton, S. D., Moehl, K., Donahoo, W. T., Marosi, K., Lee, S. A., Mainous III, A. G., Leeuwenburgh, C., & Mattson, M. P. (2018). Flipping the Metabolic Switch: Understanding and Applying the Health Benefits of Fasting. Obesity, 26(2), 254-268. https://doi.org/https://doi.org/10.1002/oby.22065
Cho, Y., Hong, N., Kim, K.-w., Cho, S. j., Lee, M., Lee, Y.-h., Lee, Y.-h., Kang, E. S., Cha, B.-S., & Lee, B.-W. (2019). The Effectiveness of Intermittent Fasting to Reduce Body Mass Index and Glucose Metabolism: A Systematic Review and Meta-Analysis. Journal of Clinical Medicine, 8(10), 1645. https://www.mdpi.com/2077-0383/8/10/1645
Cui, Y., Cai, T., Zhou, Z., Mu, Y., Lu, Y., Gao, Z., Wu, J., & Zhang, Y. (2020). Health Effects of Alternate-Day Fasting in Adults: A Systematic Review and Meta-Analysis [Systematic Review]. Frontiers in Nutrition, 7. https://doi.org/10.3389/fnut.2020.586036
References
Currenti, W., Buscemi, S., Cincione, R. I., Cernigliaro, A., Godos, J., Grosso, G., & Galvano, F. (2021). Time-Restricted Feeding and Metabolic Outcomes in a Cohort of Italian Adults. Nutrients, 13(5).
de Cabo, R., & Mattson, M. P. (2019). Effects of Intermittent Fasting on Health, Aging, and Disease. New England Journal of Medicine, 381(26), 2541-2551. https://doi.org/10.1056/NEJMra1905136
He, S., Wang, J., Zhang, J., & Xu, J. (2021). Intermittent Versus Continuous Energy Restriction for Weight Loss and Metabolic Improvement: A Meta-Analysis and Systematic Review. Obesity, 29(1), 108-115. https://doi.org/https://doi.org/10.1002/oby.23023
Hussin, N. M., Shahar, S., Teng, N. I. M. F., Ngah, W. Z. W., & Das, S. K. (2013). Efficacy of Fasting and Calorie Restriction (FCR) on mood and depression among ageing men. The journal of nutrition, health & aging, 17(8), 674-680. https://doi.org/10.1007/s12603-013-0344-9
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Meng, H., Zhu, L., Kord-Varkaneh, H., O Santos, H., Tinsley, G. M., & Fu, P. (2020). Effects of intermittent fasting and energy-restricted diets on lipid profile: A systematic review and meta-analysis. Nutrition, 77, 110801. https://doi.org/https://doi.org/10.1016/j.nut.2020.110801
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