Current evidence suggests that a vegan diet is not superior to an omnivorous diet in terms of enhancing performance or recovery in athletes. In other words, vegan or not, the diet has to be balanced and deliver all macro- and micronutrients in order to support optimal physical performance. In this detailed article, which I, for convenience of reading, divided into two parts, I will cover the most important nutrients in the context of physical performance.
Part one of the article covers calories, carbohydrates, protein, creatine and beta-alanine. Part two of the article covers micronutrients iron, calcium, vitamin B12 and vitamin D.
In general, people who follow a vegan diet intuitively (this is to say without paying attention to specific nutrients) have a suboptimal intake of protein, iron, calcium, vitamin B12 and vitamin D. Therefore, optimal vegan sports nutrition requires (more) careful consideration, planning and evaluation.
Calories
To start with, for most athletes, a well-constructed diet (vegan or otherwise) should provide sufficient energy in order to achieve energy balance. In other words, you need to consume enough calories to cover your energy needs. But! High intensity training can reduce appetite, which can lead to the opposite – caloric deficiency.
The consequences of structural insufficient energy can be detrimental. Immune function can become compromised, leading to illnesses and time off from training and competition. Further, unintended weight loss due to caloric deficit can lead to reduced strength and loss of muscle mass.
Protein
In general, the protein requirement of endurance athletes is less than that of strength athletes. Vegan endurance athletes are recommended to consume 1.2 – 1.4 grams of protein per kilogram of bodyweight per day.
Strength athletes who want to focus specifically on increasing muscle mass are advised to (temporarily) take more protein than the general population. Depending on the athlete’s fitness and goals, the extra amount of protein can range from 1.2 to 2 grams of protein per kg of body weight per day. For a strength athlete who weighs 60 kilos, this amounts to between 72 and 120 grams of protein per day. The upper limit of protein requirements can be as high as 2.2 grams of protein per kilogram of body weight per day, but studies have shown that most muscle growth in healthy individuals peaks at around 1.6 grams. That is, there is a limit to muscle growth, and eating more protein (over 1.6 g/kg) is unlikely to help.
Skeletal muscle mass is regulated through dynamic fluctuations in muscle protein synthesis (MPS) and muscle protein breakdown rates. Periods where MPS exceeds muscle protein breakdown will result in the net cumulation of muscle protein, whereas periods where muscle protein breakdown exceeds MPS will result in the loss of muscle mass.
Vegan athletes appear to consume less protein than their omnivorous and vegetarian counterparts. And the protein they consume is in general of a lower quality. Plant protein sources are often limiting in one or more essential amino acids, and typically contain less Branched Chain Amino Acids (BCAA) than animal proteins. Common examples of the limiting amino acids in plant-based proteins include lysine, methionine, isoleucine, threonine and tryptophan. Of these, lysine appears to be most commonly absent, particularly from cereal grains. However, beans, lentils, peas and tree nuts are all good sources of lysine. Therefore, consuming these foods on a daily basis is important for athletes.
If you want to learn more about protein in relation to vegan diets and physical performance, please read this detailed article.
Carbohydrates
Carbohydrates are also a very important macronutrient in the context of sport. Vegans generally consume more carbohydrates than omnivores. So, an adequate carbohydrate intake via a vegan diet is rarely a problem. However, it is good to realize that foods rich in carbohydrates (grains, beans, nuts) are rich sources of fibre and therefore promote early satiation. For lean athletes this can be a disadvantage.
In order to achieve sufficient carbohydrate intake for athletes involved in intensive training it might be appropriate to select lower-fibre foods when preparing high-carbohydrate meals. Practically, this means eating regular pasta instead of wholegrain, white bread instead of wholegrain and vegetables without their skins.
Creatine
When you exercise, you use energy. Your muscles mainly get that energy from carbohydrates and fats. But it takes 6 to 8 seconds for this combustion to start. To bridge this period, your muscles rely on a natural energy supply: creatine phosphate. This substance provides your muscles with energy for the first 6 to 8 seconds.
Research indicates that vegetarian and vegan diets reduce muscle creatine stores. But it is currently unclear whether the lower creatine concentrations observed in vegans result in impaired performance or muscle hypertrophy.
Creatine supplementation might therefore be an important aid for vegan athletes to consider and to compensate for the reduced muscle creatine stores experienced as a result of their lifestyle choices.
Creatine is available as a supplement as creatine monohydrate. This supplement can help athletes perform better during short-term intensive efforts, such as weightlifting or short sprints.
Building up the creatine phosphate supply in the muscles can be done with a fast or slow method. With the fast method you take 20 to 25 grams of creatine every day over a period of 5 to 7 days (spread throughout the day). With the slow method you take 3 grams of creatine every day over a period of 28 days.
A common side effect of using a creatine monohydrate supplement is an increase in weight. This is because the amount of fluid and (not muscles) in the body increases. Further, in some cases it can cause stomach or intestinal complaints.
In about a third of people, extra creatine in the form of supplements appears to have no effect on sports performance.
Carnosine/Beta-alanine
Carnosine is a dipeptide (a molecule, made from two amino-acids, namely Beta-alanine and L-histidine) that is greatly concentrated in muscles. Vegetarians and vegans have lower levels of muscle carnosine compared to omnivores.
β-alanine supplementation has been shown to increase muscle carnosine concentrations, leading to improvements in high-intensity exercise and a reduction in fatigue.
β-alanine is exclusively found in meat and fish and is therefore completely absent from a vegan/vegetarian diet. However, whether these lower muscle carnosine concentrations result in impairments in exercise performance is not clear.
If you decide to try β-alanine out, bear in mind that the optimal intake has not been established.
Bullet points
In general, vegan diets tend to be lower in protein, and therefore attention should be given to this macronutrient.
High energy/ high carbohydrate needs can be reached using foods that are lower in fiber.
Supplementation with creatine or β-alanine might offer performance-enhancing effects in vegans, who experience low pre-existing levels of these substances, but the research is inconclusive.
Sufficient intake of micronutrients iron, calcium, vitamin B12 and vitamin D is a pre-requisite for optimal physical performance.