The Pros and Cons of Plant-Based Eating for Endurance Athletes

Former pro Ironman triathlete Brendan Brazier is clear-eyed about the challenges he faced switching to a 100% plant-based diet early on. When asked if endurance sports or veganism came first for him, the answer was definitive. “Running came first,” he said. “I wanted to speed recovery. That’s what got me looking into different ways of eating. Plant-based was one of the things I tried, and, at first, it didn’t work great for me. I wasn’t doing it right, so I started doing some basic research and found I just needed more nutrition—nutrients, not just eating pasta all the time.”

Brazier is a two-time Canadian 50K Ultramarathon champion who has been vegan since the 1990s. He is the author of Thrive and co-founder of Vega, a sports nutrition company, and Fire Road, a vegan meal delivery service for athletes. With a well-executed vegan diet, he soon reported faster recovery, reduced inflammation, easier digestion, better sleep, and more energy. 

According to a 2019 review of the scientific research, his experience is not surprising. The study shows plant-based diets can have a beneficial effect on “weight status, energy metabolism and systemic inflammation.” 

In recent years, the success of athletes such as Venus Williams, Colin Kaepernick, Alex Morgan, former pro triathlete Hillary Biscay, ultramarathoner Scott Jurek, and cyclist and Olympian Dotsie Bausch have given rise to new interest in plant-based nutrition. But what is required for a vegan diet to work for endurance athletes, and what are the possible drawbacks?

RELATED: Triathlete’s Complete Guide to Nutrition and Fueling

Getting adequate calories

The importance of adequate calories seems to be a recurrent issue when talking to endurance athletes, registered dieticians, and authors about the plant-based approach. Ultrarunner Matt Frazier, co-author of The Plant-Based Athlete and founder of No Meat Athlete, said: “Calories are the challenge. A lot of athletes go plant-based and a month later, they’ll say, ‘I didn’t have any energy, so I went back.’ Many times, it’s because they inadvertently reduced their calories by 25%. They stopped eating all the calorically-dense foods that they were consuming and replaced them with salad, vegetables, or fruit. You’re getting a ton of nutrition, but you really do need to make sure you get enough calories from meals that are designed to be a plant-based with more calorically-dense things like sweet potatoes, beans, avocado, and nuts and seeds.”

When exploring a vegan diet, Frazier recommends getting “a sense of how many calories you’re currently eating and and what the macronutrient breakdown is. It’s worth noting roughly where you are so you can make adjustments.”

RELATED: The Right Way to Calculate Calories Burned in Training

Pay attention to micro-nutrients, not just the macros

According to New York City registered dietician, Paula Doebrich: “With a well-planned, plant-based diet, some people could see an improvement in performance, as the diet is rich in antioxidants that help fight off oxidative damage, potentially speeding up recovery. A plant-based diet may also help reduce body weight, and, if this is something that is desirable, it could potentially improve performance.”

However, she cautions that athletes making the switch need to be mindful of a few essential nutrients that can be inadequate or absent in vegan diets. “Athletes need to make sure they are getting sufficient iron. This is especially true for female athletes. Iron is needed to carry and deliver oxygen throughout the body, so a deficiency will impair work capacity. Vitamin B12 is another nutrient of concern. This nutrient is needed for energy metabolism and a deficiency will lead to diminished performance. Poorly planned plant-based diets may be low in vitamin D and calcium, which are both essential for healthy bones.”

To help mitigate this, be sure to seek out iron in foods such as dark leafy greens, tofu, lentils, and beans. Many cereals and plant-based milks are fortified with calcium and vitamin D. Sunlight also boosts vitamin D, and vitamin B12 can be found in fortified foods and nutritional yeast. Of course, many athletes utilize supplements for these essential nutrients, as well.

“No meat” doesn’t mean “not enough protein”

Protein is a top concern for many athletes considering a plant-based diet, but registered dietician nutritionist and ACE-certified personal trainer Sarah Skovran explained that the idea that getting enough protein is problematic without eating meat is a common misconception. She said: “A well-balanced vegan diet is rarely deficient in total protein. Any single plant-based food will not typically contain all of the necessary amino acids (building blocks of protein), but it’s easy to make sure you’re getting them all by eating both grain foods and legumes or nuts every day.”

Brazier agreed: “Protein is the classic question. You do want to make sure you have enough, but, switching to whole foods, it’s not hard. A slice of sprouted bread has six or seven grams of protein, the same amount that’s in an egg. To keep on enough muscle, I do still have a protein shake every day after I work out with pea, rice, or hemp proteins.”

RELATED: Go Beyond Tofu With These Plant-Based Proteins

Time it right

Timing of meals is another important consideration—and of course that’s true of any athlete, not just those following plant-based diets. Frazier said: “As a plant-based athlete, you’re going to fill up at mealtimes, but you will digest that food pretty quickly. I found I could eat more frequently with substantial snacks between lunch and dinner. For example, it’s not hard to get 500 extra calories by eating pita with hummus and olive oil or some almond butter on an apple. Just make sure you eat frequently enough because you’ll feel full, but you’ll be hungry sooner.”

Before an intense workout, Brazier prefers quick energy like date bars with a few nuts and seeds. Before and after six-hour rides or three-hour runs, he relies on protein to maintain muscle, and, in the evening, he’ll have a big salad and pack in some sprouted nuts and seeds, a good source of protein like tempeh and high-quality fat like avocado.

RELATED: Yes, You Can Make Muscle on Plant Protein

Making informed decisions about plant-based eating

Some athletes turn to plant-based diets for ethical and environmental reasons. Others are purely curious about the physiological and performance effects. These diets can require extra planning, but the impact of more plant food in any diet is evident.

A 2019 study in Nutrients titled “Plant-Based Diets for Cardiovascular Safety and Performance in Endurance Sports” reported that plant-based diets “may provide a substantial measure of cardiovascular protection. In addition, plant-based diets may offer performance advantages. They have consistently been shown to reduce body fat [and]… foster effective glycogen storage… improve vascular flow and tissue oxygenation. Because plant-based foods are rich in antioxidants, they help reduce oxidative stress [and]… indicators of inflammation. These features of plant-based diets may present safety and performance advantages for endurance athletes.”

The consensus is that a balanced vegan diet can offer adequate nutrition to fuel most athletes, but everyone’s body is unique. For those who are curious to give it a try, resources for information are more abundant than ever, and, as the experts all agree, the best place to start is by listening to your own body.  

RELATED: Triathlon is Part of Vegan Entrepreneur Dominick Thompson’s Success