The effects of a vegan/vegetarian diet on endurance/endurance athletes:

Author: Kayla Strodtman

Recently, there seems to be an increase in the prevalence of vegan and vegetarian diets across the country. Those of us who hate vegetables or love a good burger may question the point of a seemingly dull diet like this. Those who are focused on living a high intensity lifestyle may ponder this diet the most. Does a vegan or vegetarian diet have any effect, specifically any positive effect, on our endurance and in athletes?

One factor of our endurance is the abilities of our lungs to function, or our cardiorespiratory response. A study done by Leischik and Spelsberg (2014), looked at the vegan ultra-athlete and 10 non vegan Ironman triathletes, in order to analyze any effects of the vegan diet. Echocardiography and spiroergometry, two instruments used to measure heart and lung capacity, were used to test the respiratory ability of both athletes. It was found that the ultra-athlete, who was a vegan, had a higher oxygen intake at the respiratory compensation point. The respiratory compensation point is the point at which maximal exertion can be assumed. An increase in oxygen intake allows for a greater amount of oxygen to be utilized by the working muscles at this maximal point, which ultimately leads to greater endurance performance.

Another important aspect of endurance performance is the functions of the cardiovascular system. A study done by Fontana et al. (2007), analyzed the effects of vegetarian diets on endurance performance and some metabolic factors. 21 subjects that had previously been consuming vegetarian diets and 21 subjects that had been consuming a normal western diet were compared. It was found that those partaking in the vegetarian diet had lower systolic and diastolic blood pressures that were associated with the uptake of sodium, fiber, and potassium. Vegans tend to have a higher intake of these nutrients, due to their diet. In conclusion of this experiment, it was found that the vegetarian diet leads to low cardiometabolic risk, specifically in relation to an overall lower blood pressure.

Overall, there are many factors that go into our endurance, performance, and overall health. Many different studies have analyzed numerous different factors, and the effects that a vegan/vegetarian diet would have on them. There are both pros and cons to the diet. An article from the New York Times, (Reynolds 2012), states some of the negative effects of a vegan diet for athletes. One main down side to a vegan diet is the lack of protein. There are many ways to incorporate protein rich foods into a vegan diet, however it is something that people definitely have to be more aware of, and may not always get enough of. Some sources of protein for vegans and vegetarians include nuts, beans, and tofu. An even bigger factor discussed in this article was B12, which only comes from meat. B12 effects red blood cell production, which is important for endurance since they transport oxygen to tissues throughout the body. Like protein, there are other ways that vegans can get B12 into their diets, but it is something they have to look for and be aware of in order to maintain a healthy level of it. B12 is slightly easier for vegetarians to consume as it can be found in eggs and whole milk. It is a little more difficult for vegans, as B12 is only mostly found in plant based meats or certain fortified foods. Similarly to B12, iron also effects red blood cell and hemoglobin production and is a more difficult nutrient for vegans to consume, as it is prominently found in meats. The best ways for vegans to receive iron is by consuming tofu and dark leafy greens. One nutrient that is prevalent in a vegan/vegetarian diet is carbohydrates. This is a positive of the diet. Reynolds (2012) also discusses this. Carbohydrates are a primary fuel source, and high sources of fuel are needed for endurance athletes. A study by Wirnitzer et al. (2016) analyzed the prevalence of vegans and vegetarians. Her studies found that 5% of the European population is vegetarian, while up to 9% of the population in Germany is vegetarian. It is becoming an increased custom across the world. This study also makes notes of numerous endurance athletes, including Olympians and famous marathoners, that function on vegan or vegetarian diets. Some of these athletes include Venus Williams, Carl Lewis, and Bode Miller, all of which were Olympians. With this increase in prevalence across many regions and among many prominent athletes, there should be a strong push for increased studies into the effects of these diets on athletes and athletic performance.


Wirnitzer, K. et al. (2016). Prevalence in running events and running performance of endurance runners following a vegetarian or vegan diet compared to non-vegetarian endurance runners: the NURMI Study. SpringerPlus. 5, 458. DOI 10.1186/s40064-016-2126-4

Reynolds, G. (2012). Can athletes benefit from a vegan diet? The New York Times. Pg. D6.

Cotes, J. et al. (1970). Possible effect of vegan diet upon lung function and the cardiorespiratory response to submaximal exercise in healthy women. The Journal of Physiology, 209(1).

Leischik, R., Spelsberg, N. (2014). Vegan triple-ironman (raw vegetables/fruits). Case Reports in Cardiology.  DOI:10.1155/2014/317246

Fontana, L, et al. (2007). Long-term low-calorie low-protein vegan diet and endurance exercise are associated with low cardiometabolic risk. Rejuvenation Research, 10(2), 225-234.