The last thing you want to do is try to push a vegan customer onto a meat-based diet. But I get questions about how a vegan diet affects athletic performance, so that’s the topic of this article.
There may not be enough long-term research yet to draw definitive conclusions, but we can still discuss aspects of the topic.
What about protein for vegans?
Women and men who exercise need protein levels well above the RDA. The RDA levels are 0.8 g per kilogram of body weight per day, so maybe 46 g for women and 56 g for men, on average. The protein needs of athletes are higher, ranging between 1.4 g and 1.8 g per kilogram.
Reputable sources in the nutrition field point out that because vegan protein is less bioavailable than animal protein, we need more of it: about 20-25% more plant protein than animal protein. We also have to be diligent in obtaining it.
Adding a few chickpeas to your salad will not be enough. You can drink several cups. The same goes for tofu: a small piece of a tofu “cake” will not be enough; you probably need everything.
Because plant protein often contains fairly high levels of carbohydrates, it can be quite filling and make it difficult to get enough protein in any given meal. Instead, spread out your protein “dose” throughout the day.
What about specific nutrients in vegan diets?
Vegan sources of iron include lentils, soybeans, quinoa, brown rice, oatmeal, nuts, seeds, Swiss chard, kale. But plant iron is less bioavailable than animal sources. Combining them with fermented vegetables, such as sauerkraut, will help increase iron absorption due to lactic acid.
Vitamin D is an important nutrient for calcium absorption, building and maintaining strong bones, and general health. Recent discoveries suggest that exposure to sunlight does not produce adequate amounts of vitamin D, so other sources are needed. Try fortified non-dairy milks and fortified orange juice.
B12 is normally only found in meat. B12 is important for endurance athletes because it affects red blood cell production.
Again, the solution probably lies in B12-fortified foods and supplements, such as cereals, non-dairy milks, soy “meat” alternatives, and nutritional yeast.
What about hormones and appetite?
According to some reports, vegans tend to get hungry shortly after eating.
Furthermore, my clinical experience has shown that vegans can have strong cravings for carbohydrates in general and extremely intense cravings for sugar in particular.
Both phenomena may have to do with CCK (cholecystokinin), the main satiety hormone in the body.
CCK is activated when the protein enters the small intestine. It makes us feel that we have had enough food and that we do not need more. It also quenches the desire for carbohydrates, including sugar.
In a comparison study, milk casein and pea protein offered the highest satiety. But if the vegan diet provides less protein overall and little or no pea protein, CCK levels may be lower.
As a result, the desire for carbohydrates, including sugar cravings, can become quite high.
And what about brain chemistry?
When I was a training coach and nutritionist for a high-performance sports program, I made an interesting observation about vegans and indoor rowing.
Vegan rowers had a hard time concentrating on training. It was particularly notable on the rowing machines; it’s pretty easy to see when participants lose focus.
I timed the focus duration at 30 seconds (really), and even timed it for a couple of workouts to verify my observation. Another trainer in the program told me one day of a participant in his group who could only concentrate—he knew he would say exactly this—”for about 30 seconds.” That participant was vegan.
My point is: Regardless of what you say about athletes and vegan diets, protein, etc., it’s important to consider not just “body protein” but also “brain protein.” Lack of concentration is often due to a lack of specific brain chemicals (dopamine and norepinephrine) that are derived from proteins. Most protein analyzes for vegans refer only to body proteins.
For what it’s worth, I convinced one of the vegans in the training program to add animal protein to his diet in a way that would work for him. He was willing to eat fish, and the focus problem was reversed almost immediately.
Focus is essential during endurance athletic efforts and beyond, making protein essential as well.
In general, though, I don’t try to convince vegans to eat animal products. Instead, I encourage the use of vegan protein powders: plant protein, hemp protein, brown rice protein, for example. This is an exception to my general rule that food should come from whole food sources. I don’t think kale can provide enough brain protein, and protein is very important; hence the powder recommendation.
My conclusion here is that plant-based diets have a more beneficial impact on the planet, however a full vegan diet may not always be the best for endurance athletes, including triathletes.
