We know that compared to a typical western diet, vegetarian diets tend to be rich in fiber, fruits, and vegetables while being lower in saturated fat and cholesterol. Large studies like EPIC-Oxford and Adventist Health Study 2 have shown marked reductions in risks of heart disease, diabetes, and even cancer.
From an environmental perspective, switching to vegetarian diets can lower greenhouse gas emissions by as much as 63%. If everyone adopted a vegetarian diet, there could be savings of over $1 trillion annually through decreased health care costs and lost productivity.
One concern commonly expressed is that vegetarian diets cannot be used by athletes. In fact, the myth is that adopting a vegetarian diet will make it very difficult for athletes to consume adequate protein and impede athletic performance. Fortunately, there are very elegant studies addressing exactly these concerns.
The position paper on vegetarian diets from the Academy of Nutrition and Dietetics states that vegan and vegetarian diets meet or exceed recommended protein intakes.
When it comes to athletic performance, there is a wonderful review paper comparing effects of vegetarian and meat-based diets on athletic performance. The authors identified 327 studies of which 8 met their inclusion criteria.
The results showed no difference between vegetarian and meat-based diets on muscle strength or power, anaerobic or aerobic performance, and immune function.
Some of the limitations of the paper included the heterogeneity in the studies and short duration (4 days to 12 weeks).
Once we have longer studies, it is very likely that we may even see an advantage with vegetarian diets and athletic performance. This is because vegetarian diets tend to be high in carbohydrates and this may result in better glycogen stores. Thus, improving endurance activities. The increased phytonutrients and antioxidants in vegetarian diets may also help with reduced oxidative stress and improved general immunity. This may be very helpful in recovery. Lastly, vegetarian diets tend to be more alkaline than meat-based diets. Since intramuscular acidity can reduce high-intensity workouts, vegetarian diets may also have an advantage.
The bottom here is that not only are vegetarian diets good for our health, our environment but they may also help us perform at our peak physical ability.