Mistakes Vegetarian and Vegan Athletes Should Avoid

Plant-Based Diets and Athletic Performance

Vegetarian and vegan questionnaire
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Vegetarian and vegan diets are rising in popularity and athletes are taking notice. There is enough evidence to support plant-based diets providing numerous health benefits, but research is lacking for athletic performance. On top of that, eating this way remains questionable because of food myths and discussions focusing more on how to avoid nutrient deficiencies rather than the benefits of eating whole foods.

However, according to the Academy of Nutrition and Dietetics (AND), "Planned vegetarian, including vegan, diets are healthful, nutritionally adequate, and may provide health benefits for the prevention and treatment of certain diseases."

Benefits of Plant Diets

Studies indicate plant-based diets provide numerous health benefits, including:

  • Reduced risk of heart disease by 40%
  • Lower low-density lipoprotein (LDL) cholesterol levels
  • Lower blood pressure
  • Lower rates of type 2 diabetes
  • Lower body mass index
  • Lower insulin resistance
  • Lower rates of cancers

Despite the positive health benefits, many active individuals and athletes accept rumors about veganism without even knowing what it means to eat vegetarian or vegan. Before exploring the common myths and mistakes among vegetarian and vegan athletes, understanding the following definitions will be helpful:

  • Vegetarian — Eats no animal flesh, but may consume eggs and dairy.
  • Vegan — Does not consume any food of animal origin. 
  • Flexitarian — Regularly follows a vegan diet, but occasionally consumes dairy, meat, fowl, or fish.

Although an optimal diet for the vegan athlete has yet to be defined, Dr. Joel Fuhrman, nutritional medicine expert for over 30 years, suggests vegetarian and vegan athletes can perform well if they choose nutrient-rich foods. His article published in Current Sports Medicine Reports suggests vegan athletes can effectively perform at high endurance levels while consuming a diet focused on micronutrient-rich whole plant foods.

Several high-profile vegan athletes, including Olympian Carl Lewis, Ironman triathlete Brendan Brazier, and tennis champion Venus Williams, have demonstrated superior athletic performance without consuming animal products. The performance of these well-known vegan athletes is remarkable but it’s only anecdotal evidence of athletic success. More research is required to dispel the common myths surrounding vegetarian (vegan) diets for athletes.

Common Myths and Mistakes

Athletes seem to have assumptions about vegetarian and vegan diets. The most common myths surround protein intake, plant proteins needing to be paired to create complete proteins, and sugar intake. The following belief systems have been popular myths over the years:

  • Fear that plant foods are unable to supply enough protein.
  • Need to pair vegetarian proteins.
  • Focus on only protein rather than a balanced diet full of phytonutrients and antioxidants.
  • Think all sugars are the same.
  • Think juice is always a no-no.

As plant-based diets have become more popular in recent years, consumers (including athletes) have gained greater awareness about vegetarian and vegan eating styles, reducing the impact of these misconceptions.

Getting Adequate Protein From Plants

Athletes require additional protein to support extreme physical demands and repair muscle protein breakdown caused by intense workouts. Adequate protein intake is essential to this process. Insufficient protein consumption can lead to a negative nitrogen balance and insufficient muscle recovery.

Plant-based diets can supply enough protein for athletes according to Nancy Clark, internationally known sports nutritionist, counselor, and author of The Sports Nutrition Guidebook. Many vegetarians and vegans are excellent athletes but that doesn’t mean they’re getting enough protein, says Clark. The problem is many athletes simply don’t eat enough. For example, it’s not uncommon for female, weight-conscious athletes not to get enough protein due to consuming too small of portions per meal.

What also remains a point of confusion and disagreement among athletes and the scientific community is how much protein should be consumed for optimal body functioning. Consuming the correct amount and optimal amino acid profile is said to determine how well your body is able to recover from high levels of physical exercise. Studies indicate protein requirements can be easily met for athletes who consume meat and vegan athletes using proper dietary planning.

However, a vegan diet is typically lower in calories, protein, fat, vitamin B12, omega-3 fatty acids, calcium, and iodine when compared to ominovorous diets. Iron and zinc may also pose a concern of adequate intake.

The Academy of Nutrition and Dietetics recommend vegetarians and vegans consume a wide variety of plant-based foods to meet their protein and amino acid requirements.

Meat is a good source of protein, but plants contain protein as well. There are about seven grams of protein per ounce of meat and one ounce of pistachios contains six grams of protein. If the athlete is vegetarian, then milk, yogurt, eggs, and cheese can add additional sources of protein. For the vegan athlete, beans can add the needed protein. There is some concern regarding the anabolic effect of plant proteins as they have lower digestibility (about 60%–70% compared to animal products which are greater than 90%), lower essential amino acid content (especially leucine), and deficiencies in other essential amino acids like lysine. Planning is imperative to combat these risks.

The Academy of Nutrition and Dietetics, Dietitians of Canada, and the American College of Sports Medicine recommend 1.2 to 2.0 grams of protein per kilogram of body weight per day for athletes, depending on training.

Consuming protein in excess of 2.0 g/kg/day has shown no benefit.

Combining Plant Proteins

Remember how it was important to eat beans and rice together at one point? The once popular recommendation to combine plant proteins to achieve a complete essential amino acid profile is no longer necessary. Current research suggests vegetarian or vegan athletes can get enough protein when eating a variety of plant foods over the course of the day, rather than a single meal.

Consuming a variety of plant proteins daily provides differing amino acids and ensures all amino acids are included, according to sports nutritionist Nancy Clark. It’s not necessary to pair the proteins at the specific meals. The goal is to have 15 to 20 grams of protein per meal to supply the correct amount of protein per day, says Clark.

Plant foods including grains, legumes, nuts, and seeds are recommended for the vegan diet and ensure essential amino acids (EAAs) and branch chained amino acids (BCAAs) are available for optimal body function and muscle recovery. Excellent sources of quality plant protein can be found in the following whole foods:

  • Edamame
  • Lentils
  • Quinoa
  • Tofu
  • Black beans
  • Pumpkin seeds
  • Almonds
  • Oats

Protein Intake vs. Balanced Diet

Many vegetarian or vegan athletes believe they need to focus on consuming more protein to meet daily requirements. Protein intake is essential but consuming all macronutrients including carbohydrates and healthy fats are just as important for athletic performance. The problem for many of these athletes is not considering the role of carbohydrates in muscle function, growth, and recovery.

According to sports nutritionist Nancy Clark, many athletes are working out but only consuming a protein drink. These drinks lack the necessary glucose and other nutrients coming from carbohydrates to properly refuel their muscles. Eating a balanced diet pre and post workout satisfies macronutrient requirements for optimal athletic performance.

Consuming a wide variety of plant foods not only provides protein, but also the energy to complete intense workouts. Eating a plant-based diet also supplies the body with essential phytonutrients and antioxidants necessary for working muscles. Foods high in phytonutrients and antioxidants may reduce the effects of excess inflammation and promote recovery from physical training.

The following green vegetables provide protein, micronutrients, and antioxidants: 

  • Asparagus
  • Avocado
  • Brussels sprouts
  • Broccoli
  • Corn
  • Potato

The following fruits are high in antioxidants:

Sugar Is Sugar

Most vegetarian and vegan athletes stay away from sugar mostly because of the refining process. Refined sugar is bleached using bone char filters. The sugar doesn’t actually contain bone particles, but the sugar has come in contact with the sterilized animal bone. Not all sugar is processed this way so really can’t be considered the same. There are sugars considered acceptable in a plant-based diet. Beet and coconut sugar aren't processed using bone char filters. However, keeping sugar intake to a minimum is still recommended for general health.

Athletes require more sugar compared to the average American according to sports nutritionist Nancy Clark. Sugar is the gas in the car and required to refuel working muscles. Post recovery drinks like chocolate milk contain sugar but also essential vitamins and minerals essential for optimal body function and athletic performance.

Refined sugar may be perceived as less healthy than beet sugar or agave nectar but the body reads sugar as sugar. All sugar contains 4 calories per gram and is a subcategory of carbohydrates. There are five different sugar types:

  • Glucose — Simple sugar also called dextrose and commonly referred to as blood sugar. 
  • Fructose — Simple sugar also called fruit sugar quickly absorbed by the body.
  • Galactose — Simple sugar found in milk and yogurt slowly absorbed by the body.
  • Maltose — Simple sugar also called malt sugar quickly absorbed by the body.
  • Lactose — Also called milk sugar and contains glucose and galactose. 

Sugar is the primary energy source used during exercise. The following sugars are considered acceptable for vegetarian/vegan diets:

  • Agave
  • Brown rice syrup
  • Maple syrup
  • Date syrup
  • Molasses
  • Stevia
  • Beet sugar
  • Coconut sugar
  • Honey
  • Vegan granulated sugar

Endurance athletes, especially, benefit from consuming more sugar in order to support increased glucose uptake into the muscle cells. Without adequate sugar (energy) to fuel your muscles, you won't perform as well when exercising.

Should I Avoid Drinking Juice?

Athletes, in general, assume juice is nothing but sugar and shouldn’t be included in a healthy diet. Juice concentrates contain natural fruit juice mixed with lots of water compared to sugar-added juice cocktails. It’s the type of juice being purchased that can be problematic. Pure juice from concentrate (especially if fortified with calcium) is routinely recommended by sports nutritionists and registered dietitians to help high-endurance athletes meet daily caloric requirements.

Many athletes struggle to maintain a healthy weight loss because of the physical demands of their sport. Adding a glass or two of 100 percent juice instead of water daily has helped these athletes gain and maintain an appropriate weight or to refuel muscles adequately. Sometimes food just isn’t enough and juice provides that additional boost for athletes who need lots of calories to meet physical demands. Athletes who may benefit from adding juice to their nutrition programs include high school athletes, long-distance runners, triathletes, and cyclists.

More Research

Research has shown plant foods beneficial to improve health and reduce disease risk factors, but little evidence exists showing the effects of these diets on athletic performance. Because vegetarian, vegan, and combination plant-based diets are being adopted by athletes, more studies are starting to surface.

For instance, a 2019 study compared the running performance of 76 recreational athletes who followed a vegan, lacto-ovo-vegetarian, or omnivorous diet. Data collected indicated that each diet has neither advantages nor disadvantages with regard to exercise capacity. Study authors wrote that their results "suggest that a vegan diet can be a suitable alternative for ambitious recreational runners."

A small study published in the journal Nutrients measured cardiorespiratory fitness between vegetarian and omnivore (meat-eating) endurance athletes. Results indicated the vegetarian female athletes had higher oxygen uptake values (VO2 max) and equivalent strength compared to omnivore counterparts. No significant differences were seen in males. Overall, the cardiorespiratory function of the vegetarian groups was higher, but the there was no difference in peak performance between the groups. Researchers concluded that a vegetarian diet can support the strength and cardiorespiratory requirements for athletes. A limitation of the study was that there were varied levels of experience in each participant's respective sport.

Other research conducted by Baylor University Medical Center followed the dietary intake of a female vegan cyclist during an 8-day mountain bike stage race. The athlete consumed over the recommended carbohydrates to maintain her stamina and performance. Her protein intake was also higher than recommended for vegetarian athletes. She was able to sustain faster times compared to non-vegan cyclists participating in the race. Results indicated a well-planned vegan diet is compatible with ultra-endurance mountain biking.

A study was published in Case Reports of Cardiology and examined the effects of a vegan diet on an ultra-triathlete (Triple-Ironman). Results indicated that a vegan diet provides similar athletic performance compared to an athlete using a conventional mixed diet. The report further suggests a well-planned vegan diet can apparently be adopted by ultra-endurance athletes without risk to health necessarily being incurred.

A Word From Verywell

Vegan diets continue to rise in popularity and are shown to provide numerous health benefits. Although research is lacking in plant-based diets and athletic performance, there are well-known vegan athletes who are achieving athletic success. What appears to cause continued confusion are the myths behind veganism and lack of research to debunk these untruths. More focus on the positive health benefits of eating mostly plant foods would help dispel concerns surrounding vegetarian and vegan diets.

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  1. Kahleova H, Levin S, Barnard N. Cardio-metabolic benefits of plant-based dietsNutrients. 2017;9(8):848. doi:10.3390/nu9080848

  2. Melina V, Craig W, Levin S. Position of the academy of nutrition and dietetics: vegetarian diets. Journal of the Academy of Nutrition and Dietetics. 2016;116(12):1970-1980. doi:10.1016/j.jand.2016.09.025

  3. Fuhrman J, Ferreri DM. Fueling the vegetarian (vegan) athlete. Curr Sports Med Rep. 2010;9(4):233–241. doi:10.1249/JSR.0b013e3181e93a6f

  4. Thriving on Plants. Many athletes are choosing plant-based diets. Updated 2017.

  5. Jäger R, Kerksick CM, Campbell BI, et al. International Society of Sports Nutrition Position Stand: protein and exerciseJ Int Soc Sports Nutr. 2017;14:20. doi:10.1186/s12970-017-0177-8

  6. Nancy Clark. Sports nutrition myths: Busted!. Updated November 2019.

  7. Dideriksen K, Reitelseder S, Holm L. Influence of amino acids, dietary protein, and physical activity on muscle mass development in humansNutrients. 2013;5(3):852-876. Published 2013 Mar 13. doi:10.3390/nu5030852

  8. Rogerson D. Vegan diets: practical advice for athletes and exercisersJ Int Soc Sports Nutr. 2017;14:36. doi:10.1186/s12970-017-0192-9

  9. Craig WJ, Mangels AR. American Dietetic Association. Position of the American Dietetic Association: vegetarian dietsJ Am Diet Assoc. 2009;109(7):1266–1282. doi:10.1016/j.jada.2009.05.027

  10. Ahnen RT, Jonnalagadda SS, Slavin JL. Role of plant protein in nutrition, wellness, and healthNutr Rev. 2019;nuz028. doi:10.1093/nutrit/nuz028

  11. Berrazaga, I.; Micard, V.; Gueugneau, M.; Walrand, S. The role of the anabolic properties of plant- versus animal-based protein sources in supporting muscle mass maintenance: A critical reviewNutrients 2019, 11, 1825. doi:10.3390/nu11081825

  12. Academy of Nutrition and Dietetics. Eat Right. Protein and the athlete - How much do you need?. Updated July 2017.

  13. Delimaris I. Adverse effects associated with protein intake above the recommended dietary allowance for adultsISRN Nutr. 2013;2013:126929. doi:10.5402/2013/126929

  14. Lynch H, Johnston C, Wharton C. Plant-based diets: Considerations for environmental impact, protein quality, and exercise performanceNutrients. 2018;10(12):1841. doi:10.3390/nu10121841

  15. Nancy Clark. Thinking about becoming a vegan athlete?. Updated December 2019.

  16. Tuso PJ, Ismail MH, Ha BP, Bartolotto C. Nutritional update for physicians: plant-based dietsPerm J. 2013;17(2):61–66. doi:10.7812/TPP/12-085

  17. Kanter M. High-quality carbohydrates and physical performance: Expert panel reportNutr Today. 2018;53(1):35–39. doi:10.1097/NT.0000000000000238

  18. U.S. Department of Agriculture. Dark Green Leafy Vegetables. Updated August 2016.

  19. Carlsen MH, Halvorsen BL, Holte K, et al. The total antioxidant content of more than 3100 foods, beverages, spices, herbs and supplements used worldwideNutr J. 2010;9:3. doi:10.1186/1475-2891-9-3

  20. Nancy Clark. The great sugar debate. Updated December 2018.

  21. U.S. Department of Agriculture. National Agricultural Library. How many calories are in one gram of fat, carbohydrate, or protein?. Updated 2020.

  22. Mul JD, Stanford KI, Hirshman MF, Goodyear LJ. Exercise and regulation of carbohydrate metabolismProg Mol Biol Transl Sci. 2015;135:17–37. doi:10.1016/bs.pmbts.2015.07.020

  23. Vitale K, Getzin A. Nutrition and supplement update for the endurance athlete: Review and recommendationsNutrients. 2019;11(6):1289. doi:10.3390/nu11061289

  24. Craig WJ. Health effects of vegan dietsAm J Clin Nutr. 2009;89(5):1627S–1633S. doi:10.3945/ajcn.2009.26736N

  25. Nebl J, Haufe S, Eigendorf J, Wasserfurth P, Tegtbur U, Hahn A. Exercise capacity of vegan, lacto-ovo-vegetarian and omnivorous recreational runnersJ Int Soc Sports Nutr. 2019;16(1):23. Published 2019 May 20. doi:10.1186/s12970-019-0289-4

  26. Lynch HM, Wharton CM, Johnston CS. Cardiorespiratory fitness and peak torque differences between vegetarian and omnivore endurance athletes: A cross-sectional studyNutrients. 2016;8(11):726. doi:10.3390/nu8110726

  27. Wirnitzer KC, Kornexl E. Energy and macronutrient intake of a female vegan cyclist during an 8-day mountain bike stage raceProc (Bayl Univ Med Cent). 2014;27(1):42–45. doi:10.1080/08998280.2014.11929052

  28. Leischik R, Spelsberg N. Vegan triple-ironman (raw vegetables/fruits)Case Rep Cardiol. 2014;2014:317246. doi:10.1155/2014/317246