If you’ve been following our work at the T. Colin Campbell Center for Nutrition Studies for a while, you’ve probably already seen some resources we have dedicated to athletes, including dozens of articles featuring anecdotal success stories and practical guides for improving your fitness. These resources are inspirational and useful; if you’re curious to check them out and haven’t done so yet, here are a few to get you started:

• Plant-Based Weight Loss: Maximize Your Exercise Plan
• Fiona Oakes Has Extreme Grit: Interview with a Plant-Based Ultramarathoner
• Bone and Muscle Strengthening Workout: Exercises to Prevent Osteoporosis
• Former NBA Player John Salley Creates a Better Life
• 5 Tips for Making Your Home Workout Fun and Sustainable
• From Obese Boy with Hypertension to Plant-Based Gym Owner

In this article, we’re going to take a deeper dive into the science behind those success stories and how-to guides. We’ll focus more on the research and, along the way, answer several of the most common questions about plant-based nutrition and athletic performance.

Will a Whole Food, Plant-Based Diet Negatively Impact My Performance?

The short answer is no.

In his 2020 book, The Future of Nutrition, Dr. T. Colin Campbell describes seminal research conducted at Yale more than a century ago in which plant-based subjects outperformed their omnivorous counterparts. In those studies, researchers discovered that even sedentary vegetarians outperformed meat-eating athletes in basic endurance tests.^[1]

But those were relatively small studies. And they studied only a narrow scope of athletic performance. What makes those experiments even more compelling is that numerous more recent studies have confirmed plant-based diets do not inhibit performance. Many of these studies show that, if anything, healthy plant-based diets are far more likely to enhance than to undermine performance. Here are just a few of the highlights from research published in the past few years:

• “The study [a review of research published from 1986–2024] showed that a plant-based diet can be considered an advantageous option for athletes, as in addition to not negatively influencing sporting results, it can strategically optimize performance and improve health.”^[2]
• “This [cross-sectional] study suggests that following a vegetarian diet may adequately support strength and cardiorespiratory fitness development, and may even be advantageous for supporting cardiorespiratory fitness.”^[3]
• “Plant-based diets have emerged as athletic performance enhancers for various types of exercise . . . [They] have demonstrated a moderate but positive effect on aerobic performance . . . On the other hand, these diets do not jeopardise strength/power performance.”^[4]
• “Vegans had a significantly higher estimated VO2 max [a measure of body’s ability to use oxygen] . . . and submaximal endurance time to exhaustion compared with omnivores [in a study of physically active women].”^[5]
• “The higher VO2 max reached by the vegan athletes may imply that they are better trained than the control . . . However, the weekly training frequency and running distances were similar in both groups . . . The vegan diet may be associated with certain, most likely positive, characteristics in echocardiography.^[6]

The experiences of athletes at the highest level reflect these findings. Again in The Future of Nutrition, Dr. Campbell highlights numerous examples of modern athletes excelling and improving performance after switching to an exclusively plant-based, or at least plant-forward, diet. These examples include far more than only long-distance runners, whom you might expect to dominate such a list. Rather, it is composed of “both endurance and power athletes, in as many sports as you can think of, across the globe.”^[7]

The documentary film Game Changers also did a good job highlighting several of the more famous examples, including a sizable contingent of the Tennessee Titans NFL team. Other examples include individuals at the highest levels in tennis (e.g., Venus Williams, Serena Williams, and Novak Djokovic), both short- and long-distance running events (Carl Lewis, Scott Jurek), basketball (John Salley, Kyrie Irving), soccer (Héctor Bellerín, Alex Morgan), wrestling (Chris Campbell), golf (Gary Player), formula one racing (Lewis Hamilton), and more.

Some might wonder whether the diet is, counterintuitively, better suited to elite athletes than to amateurs who do not have access to elite-level meal planning and chefs. In other words, maybe elite athletes have more of the resources needed to craft ideal plant-based meals at a level that others cannot match? But this speculation is not supported by the evidence. If anything, the prevalence of vegetarianism and veganism at the amateur level, particularly in endurance sports, suggests that individuals at all levels are enjoying the benefits.^[8]

What Explains the Performance Benefits of Plant-Based Diets?

The SWAP-MEAT Athlete study, a 2022 randomized crossover trial, highlights a few of the ways plant-based diets can enhance performance, including the diet’s high carbohydrate content, anti-inflammatory compounds, and combination of high fiber and low fat—in other words, several of the same factors that can explain the plant-based lifestyle’s health benefits more broadly.^[9]

“Athletes may be missing the benefits of plant-based diets,” write the authors of the study, “by overemphasizing animal products and protein intake.” This, again, mirrors the general population.

The SWAP-MEAT study is interesting for including not one but two kinds of plant-based diets, a whole-food plant-based (WFPB) diet and a plant-based meat alternatives (PBMA) diet, plus the regular omnivorous diet. The PBMA diet included branded items from Beyond Meat, Impossible Foods, or Gardein. The bottom line finding was that the plant-based diets trended toward an increase in VO2 max measures, echoing the studies referenced earlier; however, the trend was not statistically significant. One reason for this lack of statistical significance may be that the study was not as long enough or as large as would be considered ideal, with the athletes only spending four weeks on each dietary protocol.

Despite that limitation, the study stands apart for including two types of plant-based diets. Also, by focusing on recreational athletes, not elite athletes, their findings may be more relevant to the general population. One of the interesting and perhaps unexpected findings, tangential to the evidence pointing toward plant-based diets being suitable and perhaps beneficial to aerobic performance, was that the WFPB diet scored higher than the PBMA diet on most of the diet satisfaction measures: “PBMA scored lowest on 80% of categories, with notably lower scores for ease of purchase and likeability. Participants also said it required more effort to adhere to PBMA.” This contradicts what many assume about plant-based meat alternatives—namely, that they provide a more convenient and palatable alternative to animal foods.

In another study that found increased VO2 max and prolonged endurance in vegetarian athletes, the authors hypothesize that vegetarian athletes may benefit from the diet’s “effects on the number of mitochondria, capillary density, and hemoglobin concentration.”^[10] But these effects require further study. In the same study, they document significantly higher calcium and iron levels in vegetarian athletes compared to omnivores. I suspect this may come as a surprise to many athletes, who on the whole probably underestimate the calcium and iron content in plant-based staples like soybeans, tofu, and nondairy beverages.

Finally, plant-based diets can contribute to reduced body fat, improved blood flow (and therefore improved tissue oxygenation), and reduced oxidative stress, all of which can help improve athletic performance.^[11]

Can Exercise Overcome an Unhealthy Diet?

It’s easy to think of health as an accumulation of distinct factors—nutrition, stress reduction, exercise, sleep, etc. If we’re not careful, we can very easily give an imbalanced level of attention to one or two factors over the rest. This tendency may be partly human nature and partly the influence of our modern world, in which claims of magic bullet solutions are very common. We seem to want to narrow in on that one thing, that one hack, that can save us.

When we remove ourselves from this thought process, it’s easier to see its absurdity. We understand intuitively that all of these factors are inextricably linked. Going to the gym for a high-intensity interval training (HIIT) session doesn’t necessarily cancel out a six pack of beer, and eating a super healthy diet doesn’t confer the same benefits as eating well and regularly moving your body in a healthy way. If you want to improve your athletic performance, you’ll want to consider more than what you eat. “There’s no dietary substitute for quality training,” as the authors of one study wrote.^[3] I would add that there’s no substitute for proper rest or recovery, either.

Consider long-distance runners. In the minds of many people in our mostly sedentary society, anyone who has completed a marathon must be a bit of a health nut. The common perception of runners is that they are likely to be thin and to watch what they eat and drink. Surely, they’re healthier than their peers, right?

Not exactly. It depends on how we measure health. Studies have shown that, paradoxically, athletes may be more susceptible to our number one killer. More than 40 percent of middle-aged or older runners and cyclists in a 2017 study had coronary plaques; astoundingly, that was double the rate of sedentary controls!^[10] The same pattern has been found in multiple studies, and it only becomes more pronounced over time: “The degree of myocardial damage was predicted by the number of marathons run.”^[11] In a study involving men who had run the Twin Cities marathon at least twenty-five consecutive times—an impressive feat that would only be possible with a level of discipline and consistency most people would envy—researchers found “increased total plaque volume, calcified plaque volume, and non-calcified plaque volume, compared with 23 sedentary controls.”^[11]

Apart from the hundreds, or even thousands, of hours spent in preparation, what separates the marathon runner from their sedentary counterpart? The answer is in the kitchen: the runner requires far more food to compensate for the energy they expend, which can be problematic if they are eating a standard American diet. A study on the dietary quality of ultramarathon runners summarizes this problem well:^[12]

The findings indicate that ultramarathon runners who easily exceed physical activity recommendations may paradoxically consume suboptimal diets. . . . This dietary pattern may not only elevate their risk of chronic disease but also impair optimal performance by compromising recovery and adaptation to training.

What’s clear from all of the research mentioned so far is that exercise can only take us so far. We cannot outrun an otherwise unhealthy lifestyle, and when we try to do so, we may actually be doing the opposite—racing toward a premature death fueled by unhealthy foods.

Is Protein a Problem?

Athletes are most often concerned about protein. However, as highlighted in the SWAP-MEAT Study discussed above, this concern is unwarranted:^[9]

These findings contradict the popular belief that a predominately plant-based diet does not contain enough protein to support athletic performance and adaptations, and it is possible that protein is overemphasized in athletic spheres. Previous studies show that athletes and their coaches overestimate the amount of protein they need, and many mistakenly believe that protein—rather than carbohydrates—functions as the body’s primary fuel source.

Other studies back this up. For instance, a 2016 study on non-elite multisport athletes (triathletes) found that most athletes consume plenty of protein.^[13] Nearly 90 percent consumed more than 1.2 grams of protein per kilogram of body weight daily, and more than 66 percent consumed more than 1.6 grams per kilogram body weight (for context, the recommended dietary allowance [RDA]—which could be taken as a baseline for sedentary or moderately active individuals—is 0.8 grams/kilogram body weight).

In contrast, the majority of athletes in the study failed to consume the recommended intake for carbohydrates. The researchers conclude by emphasizing the need for improved nutrition education, especially given “the current negative messages about carbohydrates.”

It would be misleading and hypocritical to focus solely on carbohydrate intake, too. Instead, we should try to keep in mind the whole food context. Macronutrients do not come packaged in an isolated form, except in supplements, and our bodies do not make use of nutrients in isolation either. When athletes overemphasize protein to the detriment of carbohydrate intake, the problem isn’t only that they are failing to get carbohydrates—it’s that they’re likely not getting enough whole plant foods, and that means missing out on a lot more than carbohydrates.

More research is needed not because the evidence supporting the healthfulness of plant-based diets for athletes is insufficient but because we have a long way to go in our understanding of the potential benefits and special considerations. It’s possible that there are additional benefits we don’t yet fully appreciate.

To end on firmer footing, though, here’s what we do know: plant-based diets are associated with many health benefits, including lower body weight and reduced risk of heart disease, cancer, and type 2 diabetes. They are also better for the environment and for animal welfare, and they offer a powerful solution to what is currently a catastrophically high cost of healthcare. We can add to this list of benefits that a plant-based diet does well supporting athletic performance, regardless of the type or intensity of that performance.

References

1. Fisher I. The influence of flesh-eating on endurance. (Modern Medicine Publishing, 1908).
2. Sarmento TC, Ferreira RDS, Franco OL. Plant-Based Diet and Sports Performance. ACS Omega. 2024;9(49):47939-47950. Published 2024 Nov 7. doi:10.1021/acsomega.4c07560
3. Lynch HM, Wharton CM, Johnston CS. Cardiorespiratory Fitness and Peak Torque Differences between Vegetarian and Omnivore Endurance Athletes: A Cross-Sectional Study. Nutrients. 2016;8(11):726. Published 2016 Nov 15. doi:10.3390/nu8110726
4. Damasceno YO, Leitão CVFS, de Oliveira GM, et al. Plant-based diets benefit aerobic performance and do not compromise strength/power performance: a systematic review and meta-analysis. British Journal of Nutrition. 2024;131(5):829-840. doi:10.1017/S0007114523002258
5. Boutros GH, Landry-Duval MA, Garzon M, et al. Is a vegan diet detrimental to endurance and muscle strength? Eur J Clin Nutr. 2020;74:1550–1555. doi:10.1038/s41430-020-0639-y
6. Król W, Price S, Śliż D, et al. A Vegan Athlete’s Heart-Is It Different? Morphology and Function in Echocardiography. Diagnostics (Basel). 2020;10(7):477. Published 2020 Jul 14. doi:10.3390/diagnostics10070477
7. Campbell TC. The Future of Nutrition (with Nelson Disla). BenBella Books, Inc., Dallas TX, 2020.
8. Wirnitzer K, Tanous D, Motevalli M, et al. Prevalence of Female and Male Vegan and Non-Vegan Endurance Runners and the Potential Associations of Diet Type and BMI with Performance-Results from the NURMI Study (Step 1). Nutrients. 2022;14(18):3803. Published 2022 Sep 15. doi:10.3390/nu14183803
9. Roberts AK, Busque V, Robinson JL, et al. SWAP-MEAT Athlete (study with appetizing plant-food, meat eating alternatives trial) – investigating the impact of three different diets on recreational athletic performance: a randomized crossover trial. Nutr J. 2022;21(69). doi:10.1186/s12937-022-00820-x
10. Hernández-Lougedo J, Maté-Muñoz JL, García-Fernández P, Úbeda-D’Ocasar E, Hervás-Pérez JP, Pedauyé-Rueda B. The Relationship between Vegetarian Diet and Sports Performance: A Systematic Review. Nutrients. 2023; 15(21):4703. https://doi.org/10.3390/nu15214703
11. Barnard ND, Goldman DM, Loomis JF, Kahleova H, Levin SM, Neabore S, Batts TC. Plant-Based Diets for Cardiovascular Safety and Performance in Endurance Sports. Nutrients. 2019; 11(1):130. https://doi.org/10.3390/nu11010130
12. Craddock JC, Walker G, Chapman M, Lambert K, Peoples GE. The Diet Quality of Ultramarathon Runners Taking Part in an Australian Event: A Cross-Sectional Explorative Study. Nutrients. 2025;17(3):485. Published 2025 Jan 29. doi:10.3390/nu17030485
13. Masson G, Lamarche B. Many non-elite multisport endurance athletes do not meet sports nutrition recommendations for carbohydrates. Appl Physiol Nutr Metab. 2016;41(7):728-734. doi:10.1139/apnm-2015-0599