Nutrition of Vegetarian Athletes

Vegetarianism is a diet that is based on the consumption of plant-based foods and animal-based foods are limited or not consumed at all. Although there are varieties such as vegan, pesco-vegetarian, ovo-vegetarian, lacto-vegetarian, and lacto-ovo-vegetarian, a large amount of vegetables, fruits, grains, legumes, and nuts are consumed in general. It is evident that this diet, which has become the subject of books, movies, and documentaries in recent years, has become widespread among athletes. The expectation of a vegetarian athlete from the diet will be to provide a positive impact on exercise performance as well as on health.

The table below presents the consumed and non-consumed animal products in different types of vegetarian diets:

Potential Effects of Vegetarian Diet on Exercise Performance 

In individuals with a vegetarian diet; it is known that the risk of coronary artery disease, hypertension, diabetes, obesity and even some types of cancer is reduced. In such diets, oligosaccharides and polysaccharides, fiber, antioxidants and phytochemicals are taken in higher amounts compared to mixed diets; saturated fat and cholesterol are taken lower. An athlete who has a vegetarian diet will potetially increase her/his performance due to 4 reasons:

1. Increased glycogen stores due to high carbohydrate intake
2. Decreased oxidative stress during long-term exercise and enhanced immunity due to high intake of phytochemicals and antioxidants.
3. Improved acid-base balance due to the alkalizing effect of a vegetarian diet.
4. Helps to preserve body composition by providing early satiety due to high fiber intake.

What Do the Studies Say?

As the number of vegetarian athletes increases, the number of studies on this subject increases. In a study investigating the short-term effect of vegetarian diet on exercise performance, recreationally active individuals were assigned into two groups and tested after following either a vegetarian diet or a mixed diet for 4 days. The results of the study showed that participants on a vegetarian diet consumed more oxygen during a submaximal exercise, in other words, a vegetarian diet reduced the exercise economy ⁽¹⁾. Apart from this negative effect, no effect was found.

If we examine the long-term studies to better understand the effect of vegetarian diet; No difference was observed between the sprint performances of the two groups who followed a mixed or vegetarian diet with similar caloric intake and macronutrient patterns for 5 weeks ⁽²⁾. In another study, no difference was observed between muscle strength and power outputs of the two groups, one having a lacto-ovo-vegetarian diet and the other who was allowed to consume beef in addition to a lacto-ovo-vegetarian diet for 12 weeks ⁽³⁾_.

Considering these studies, the idea that a vegetarian diet will have a negative effect on performance is not fully supported, but it does not sufficiently confirm the claims that it increases performance. Current findings show that a vegetarian diet is no different from a mixed diet in terms of muscle strength, muscle power, anaerobic and aerobic performance. Despite these ideas, concerns remain that if a vegetarian diet is not followed properly, the risk of micro and macronutrient deficiencies may arise and exercise performance can be affected negatively by decreased muscle creatine concentrations.

On the other hand, the positive effects of a vegetarian diet on the environment are apparent. A vegetarian diet saves each day an animal, 4200 liters of water, and 20 kg of grain and reduces our carbon footprint. Even if performance is not increased with a vegetarian diet, if it is sufficient to maintain it,

Even if performance is not improved with a vegetarian diet, if the performance can be maintained in a similar way, we can consider including it in sports nutrition for a better world.

References

• Hietavala, E-M., Puurtinen, R., Kainulainen, H., & Mero, A.A. (2012). Low-protein vegetarian diet does not have a shortterm effect on blood acid-base status but raises oxygen consumption during submaximal cycling. Journal of the International Society of Sports Nutrition, 9(50). PubMed
• Baguet, A., Everaert, I., De Naeyer, H., Reyngoudt, H., Stegen, S., Beeckman, S., Derave, W. (2011). Effects of sprint training combined with vegetarian or mixed diet on muscle carnosine content and buffering capacity. European Journal of Applied Physiology, 111(10), 2571–2580. PubMed doi:10.1007/s00421-011-1877-4
• Haub, M.D., Wells, A.M., & Campbell, W.W. (2005). Beef and soy-based food supplements differentially affect serum lipoprotein-lipid profiles because of changes in carbohydrate intake and novel nutrient intake ratios in older men who resistive-train. Metabolism: Clinical and Experimental, 54(6), 769–774. PubMed doi:10.1016/j.metabol.2005.01.019