Vegetarian Athletes

Today, we discover how plant-based diets improve the performance of athletes and nonathletes alike.

In my video about comparing vegetarian and vegan athletic performance, endurance, and strength, I discussed a 2020 study that found that vegan athletes—even though they were significantly older—had significantly superior aerobic capacity and endurance, lasting 25 percent longer on a time-to-exhaustion cycling test. The question is: why? One potential mechanism that could explain the greater level of endurance performance in vegans may be a higher amount of carbohydrate intake, which could lead to better endurance performance through higher muscle glycogen storage. Other potential mechanisms that may explain the better endurance performance in vegans could be due to the anti-oxidant and anti-inflammatory profiles of their diet.

Maybe it’s even their hearts. Yet another study showing superior VO2 max in vegan athletes––meaning superior aerobic capacity. This time they also did echocardiograms, looking at their hearts in real-time using ultrasound, and the lower relative wall thickness and better main ventricle systolic and diastolic function in the vegans are most likely positive findings.

Now, wait a second; given the higher VO2 max reached by the vegan athletes, maybe they were just better trained than the nonvegan athletes, and that’s why their hearts looked like they were working better. However, the weekly training frequency and running distance were similar in both groups, suggesting benefits even with the same amount of training.

So, it’s important to educate healthcare professionals so they don’t try to discourage a vegan diet, and may even want to consider telling folks implementing an exercise training program to give it a try. But, you don’t know if it has the same kinds of effects in nonathletes, until you put it to the test.

A vegetarian vs. conventional calorie-restricted diet: the effect on physical fitness in response to aerobic exercise in patients with type 2 diabetes. Diabetics were randomized to the same caloric restriction, the same exercise, but just vegetarian versus nonvegetarian. They provided all the meals so they could ensure compliance and closely monitor the exercising.

VO2 max increased by 12 percent in the vegetarian group, significantly better than in the nonvegetarian group who didn’t significantly improve at all. Maximal performance increased by 21 percent in the vegetarian group––again, significantly better than in the nonvegetarian group, who didn’t significantly improve at all. In other words, the results indicated that more plant-based diets led more effectively to improvement in physical fitness than less plant-based diets, after the same aerobic exercise program.

It seems that those eating vegetarian were able to better burn off carbohydrates compared to nonvegetarians and had better insulin sensitivity––both markers of improved metabolic flexibility, meaning the ability to switch back and forth between burning sugar and fat.

Besides physiological mechanisms, there may also be psychological factors. They observed reduced hunger and reduced feelings of depression in the vegetarian group, which may have given them a more positive attitude toward exercise. Here’s the psychological data. Those randomized to eat vegetarian had a greater improvement in quality of life and mood. They felt less constrained, meaning the calorie restriction didn’t seem as burdensome; they had less disinhibition, meaning less tendency to binge and overeat, along with maybe less feelings of hunger. Not to mention the superior effects of a vegetarian diet on body weight, glycemic control, blood lipids, insulin sensitivity, and oxidative stress.

Wait, better body weight? I thought they were given the same number of calories. Yes, both diets were isocaloric, the same calories. Yet,  just eating meat-free led to significantly more weight loss—about six pounds more; more waist loss, a slimmer waist; lower cholesterol, of course; and less superficial fat, meaning the external jiggly fat; and most importantly, significantly more visceral fat loss––the most metabolically dangerous deep belly fat. Same calories, yet more loss of body fat. And not surprisingly, better control of their diabetes. All in addition to leading more effectively to improvements in physical fitness.

Did you know that long-term plant-based eating may improve exercise capacity and endurance? Here’s the story.

Few studies have investigated the impact of a plant-based diet on athletic performance, but the majority of the studies that have been done show no differences in endurance, performance, or strength. So, while plant-based diets do not seem to provide advantages or disadvantages on exercise performance, what plant-based diets can do is reduce the risk of chronic disease. This is a point I made in my video Why All Athletes Should Eat Plant-Based Diets, because surprisingly, endurance athletes may have more advanced atherosclerosis and more heart muscle damage, compared with sedentary individuals. So, it’s even more important they eat healthy. But, due to the favorable impact on health, it could be assumed that performance would also be influenced by plant-based diets. Let’s take a closer look at the available evidence.

This is the most commonly cited review. Studies connecting vegetarian diets to improved health are well-established; however, the evidence for this phenomenon to be transferred to improved physical performance in athletes is less clear, finding no differences—at least acutely—between a vegetarian-based diet and an omnivorous diet in muscular power, muscular strength, short burst, or endurance performance. The intervention studies in this review, however, only lasted days or weeks. So, being a vegetarian for four days may not tip the balance, or even a few months, but that’s a considerable limitation. These are people who have been eating meat their whole lives, and subsequently adopt a vegetarian diet only for the duration of the study, rather than comparing participants who have adhered to a vegetarian or meat-containing diet long-term.

This study compared exercise capacity of vegan, vegetarian, and meat-eating recreational runners and found similar maximum power output among all three groups––suggesting there’s no significant differences in maximum exercise capacity. But, that’s at the same training frequency, time, and distance. Perhaps plant-based diets might enhance recovery and allow such athletes to train longer and harder? A number of studies have come out since this review was published in 2016. What’s the update?

Well, this study compared the cardiorespiratory fitness and peak torque strength differences between vegetarian and omnivore endurance athletes. Most of the vegetarians were actually vegans, and most for at least two years, and…results from this study indicate that vegetarian endurance athletes’ cardiorespiratory fitness was greater than that for their omnivorous counterparts. They had a greater VO2 max, meaning a greater maximal oxygen uptake, greater aerobic capacity as measured on a progressive, graded, maximal treadmill test to exhaustion, though peak torque––peak strength based on leg extensions––didn’t differ between diet groups. Bottom line: these data suggest that vegetarian diets do not compromise performance outcomes and may facilitate aerobic capacity in athletes.

In this 2020 study, all the plant-based participants were eating vegan for an average of four years. So, they were essentially comparing those who ate meat for 21 years versus those who ate meat for 25 years. But after four years eating plants, you might expect to see some sort of difference. Yet, no significant differences were noted for upper and lower body muscle strength, like in the last new study. Both groups of athletes were comparable for total body weight and lean body mass, though age was significantly higher in vegans compared with omnivores; so, that put them at a little disadvantage. Yet still, there it is again. Significantly better aerobic capacity. Then, they had them pedal until exhaustion, and the vegan group lasted about 25 percent longer—12 minutes as opposed to 9 minutes. Is that just because their aerobic capacity is so high? No, even after controlling for VO2 max levels, there was still a significant endurance advantage in the vegans. The researchers conclude that in the very least, a strictly plant-based diet doesn’t seem to be detrimental to endurance and muscle strength, and endurance might actually be better in vegans, contrary to popular belief.