SWAP-MEAT Athlete Trial: The Effects of a Plant-Based Diet on Athletic Performance

Dr. Matthew NagraArticles, Plant-based Diet, Protein, Vegan Protein

Image of plant-based foods on table with weights and measuring tape surrounding them

The Effects of Diet on Athletic Performance

Researchers at Stanford University recently published a study titled the SWAP-MEAT Athlete trial. This study compared the impact of three separate diets on athletic performance amongst athletes. The first was a predominantly whole foods plant-based (WFPB) diet. This included plant-based protein sources such as tofu, beans, and quinoa as some of the primary swaps. The second was a predominantly plant-based diet with plant-based meat alternatives as the primary protein sources. And lastly, the third was an omnivorous diet where red meat and poultry were the primary protein sources.

For the WFPB diet, processed foods, dairy, and eggs were to be minimized. While fish was allowed once per week, both meat and meat alternatives were not allowed at all. On the plant-based meat alternative diet, fish was allowed once per week while meat was not allowed at all. And on the omnivorous diet, plant-based protein in the form of meat alternatives were not allowed, while fish was allowed once per week. Both the omnivorous and meat alternative diets allowed small amounts of dairy and eggs. These would typically be “hidden” in food they were consuming, rather than having a glass of milk or eggs for breakfast. Thus, they were not considered major protein sources.


Of the 22 participants who completed the trial, half were recreational endurance athletes while the other half were recreational strength athletes. Endurance athletes had been training for an average of 4.8 days per week for 5.2 years. Comparatively, the strength athletes had been training 4 days per week for 6.9 years. All participants were between the ages of 18 and 35 and were neither obese nor underweight. These participants completed all 3 diet phases (WFPB, meat alternatives, and omnivorous) for 4 weeks each in a random order while continuing to train. During this time, they had their performance evaluated after each phase with a variety of strength and/or endurance tests.


Overall, there were no significant differences in any strength or endurance outcomes between the various diets. However, the WFPB diet did result in a slightly lower bodyweight and body fat percentage compared to the omnivorous diet in both runners and strength athletes. Furthermore, the meat alternatives diet resulted in slightly lower body fat percentage compared to the omnivorous diet amongst the runners. This suggests that, although the participants reported consuming similar amounts of calories on each diet, they were likely consuming less on a plant-based diet, especially the WFPB diet. Participants also reported consuming less protein, fat, saturated fat, cholesterol, sodium, and more carbs, iron, and fibre on WFPB compared to the omnivorous diet with the meat alternative diet falling between those two.

What cannot be overstated is that the results were similar for each diet despite the lower protein and likely lower caloric intake on WFPB. I mention this because I suspect some animal protein proponents are going to point to the small, non-statistically significant differences in leg press and push-up performance between groups, which could easily be explained by a lower caloric and protein intake, rather than an inherent inferiority of a plant-based diet. Therefore, it could, in all likelihood, be overcome by simply consuming more protein and calories from plant sources, such as tofu, seitan, lentils, or a protein powder to match that of the omnivorous diet. In fact, we do have previous research on vegan vs. omnivorous diets that are matched for protein content, which do not show any significant differences in strength or muscle size outcomes between groups after 12 weeks of resistance training.

Final Thoughts

It’s worth noting that in this new study, there was one participant whose performance changed drastically between diet phases. For example, the difference of completing an extra 25-30 push-ups. However, because the results are so drastic, the differences in performance they demonstrated are unlikely due to diet. It could just be the difference between a very good and bad day at the gym; or worst case, the difference in performance could be intentional. Once this participant was removed from the analysis, the small, non-statistically significant differences in leg press and push-up performance between groups became even smaller.

Lastly, it’s worth mentioning that adherence was high. Participants rated the satisfaction of WFPB and the omnivorous diet very similarly. While the meat alternative diet was rated lower for ease of purchase and likeability. Therefore, this data adds to the evidence that a plant-based diet can support physical performance. Even in place of diets comprised of more animal protein. Moreso, it throws a giant wrench into the excuses we hear from the animal protein proponents.

Find a Plant-Based Doctor

Plant-based protein has proven to be a great meat alternative, even for those who require higher-protein levels, such as athletes. We have great access to a variety of plant-based foods, including meat alternatives. Therefore, individuals can reap the health benefits of consuming less animal products, without compromising their endurance or strength. Are you an athlete looking to adopt a plant-based diet? Perhaps you simply want to add plant-based protein swaps into your weekly routine? Plant-based doctors such as myself can help you navigate this transition to maintain your gains and maximize your health. Book an appointment today!