The short answer is yes. There are plenty of successful athletes who follow strict vegetarian or vegan diets, including serious competitive bodybuilders, powerlifters, and other high-level strength and endurance athletes.
It’s a myth that the proteins obtained from soy, nuts, seeds, and whole grains are inferior to animal-based proteins. Proteins are less concentrated in many plant sources, which means that you need to eat a higher volume of protein-rich plant-based foods to get the same amount of protein as you would obtain from an animal-based source. On the other hand, some plant sources are comparable to animal sources. For example, if you eat a little over half a cup of shelled peanuts, you’ll get as much protein as you would from a 3-ounce serving of steak.
Research on vegetarian/vegan diets vs. meat diets for athletic performance
Evidence for the effects of a vegetarian diet on strength and athletic performance is mixed, with a few studies finding in favour of non-meat diets, others in favour of diets that include meat, and many finding no major differences in outcomes. Most of these studies had small subject pools and examined training results over a very short timeframe, so it’s impossible to draw any real conclusions. However, vegetarians and vegans who choose their diets carefully can obtain all the nutrients they need for good health and high energy, so there’s no reason why meat-free diets should preclude muscle building.
Researchers have used different methods and measured different aspects of strength and general fitness, which may account for some of the differences in outcomes, but some of these differences may also be attributable to study participants eating different things. Omnivorous, vegetarian, and vegan diets can all be good or bad. A meat eater who lives on fast food hamburgers will get different training results than one who chooses lean, high-quality meats, and vegans who consume plenty of nuts and legumes will have different fitness outcomes than those who subsist largely on processed junk food or eat only salads with no added protein.
It’s easy to get enough protein from a vegetarian diet if you eat eggs and dairy products, but significantly more challenging on a vegan diet. It’s certainly possible, but requires a lot of research, commitment, and likely a bit of experimentation to find a mix of foods that provides the results you want. In addition to eating a lot of protein-rich plant foods, you’ll need to eat a large amount of food in general, as most plant-based foods are not only lower in calories, but can also prevent weight gain in other ways (for a discussion of this, see J. Gerard, “Can your vegan athletes match their meat-eating competitors?” The American Council on Exercise).
Different bodies respond differently to various foods, so what works for someone else might not work for you. Some evidence suggests that it may be easier to get lean on a vegan diet, but harder to bulk up if you’re trying to develop huge muscles. However, many people have managed to do it, so it’s certainly possible.
What are the best plant-based protein sources?
Good protein-rich foods from plant sources include:
- Soy/tofu products*
- Peanuts/peanut butter
- Other types of peas
- Whole grains
*Although concerns have been expressed about men consuming soy because it’s a phytoestrogen, research has shown that soy does not have any feminizing effects on men (Messina, 2010).
Note: B12 deficiency is a risk for those who don’t eat any animal products, but there are supplements and fortified plant-based foods available to prevent this problem.
For a summary of research comparing the muscle gains and performance of vegetarian/vegan and meat-eating athletes and bodybuilders, as well as a list of vegetarian and vegan athletes and competitive bodybuilders, see “Protein for Strength and Athletes” by Michael Bluejay, 2013.
- Forbes-Ewan, C. (2002). Effect of Vegetarian Diets on Performance in Strength Sports. Sportscience, 6.
- Haub, M. D., Wells, A. M., Tarnopolsky, M. A., & Campbell, W. W. (2002). Effect of protein source on resistive-training-induced changes in body composition and muscle size in older men. The American journal of clinical nutrition, 76(3), 511-517.
- Hutchinson, A., PhD. (2011). Which Comes First, Cardio or Weights? Fitness Myths, Training Truths, and Other Surprising Discoveries from the Science of Exercise. HarperCollins.
- Larson, E., MS, RD, LD. (1997). Vegetarian diet for exercise and athletic training and performing: an update. Issues in Vegetarian Dietetics, 6(3), 4-7.
- Messina, M. (2010). Soybean isoflavone exposure does not have feminizing effects on men: a critical examination of the clinical evidence. Fertility and Sterility, 93(7), 2095-2104.
- Nieman, D. C. (1999). Physical fitness and vegetarian diets: is there a relation? The American Journal of Clinical Nutrition, 70(3), 570s-575s.
- Pilon, M. (2012). Sculptured by weights and a strict vegan diet. The New York Times.
- Wanlass, P., Dr. (2014). Strength Training and Sports Nutrition for Men. Lulu. com.