Vegetarian Diet for Athletes – Is It Suitable?

Plant-Based Diet for Athletes

For over a decade, there’s been a noticeable increase in the popularity of diets that eliminate meat products. The motivations for adopting them include health, environmental, and ethical reasons. An increasing number of athletes, both professionals and amateurs, are choosing this nutritional approach.

At the same time, many doubts arise regarding the proper balancing of a vegetarian diet for physically active individuals. These concerns mainly revolve around the risk of deficiencies in vitamins and minerals, especially iron.

Vegetarian Diet in Sports: Where to Get Protein?

Protein is the primary building block of the human body. It is part of muscle tissue, various enzymes, immune system cells, hormones, and neurotransmitters. Due to constant metabolic processes in the body, it’s essential to provide adequate protein through diet.

Physically active people have a higher demand for protein because exercise affects muscle tissue. Moreover, protein stimulates and accelerates post-exercise regeneration and helps rebuild damaged muscle fibers.

Recommendations for daily protein intake in athletes range from 1.2 to 2.0 grams per kilogram of body weight per day (1). This amount can easily be achieved on any vegetarian diet. However, it’s crucial to meet the body’s total energy needs. Otherwise, dietary protein may not be used effectively.

Animal and Plant Proteins

Endogenous amino acids are those the body can produce on its own. Exogenous amino acids, however, cannot be synthesized by the body and must be obtained from the diet. These include:

• phenylalanine,

• isoleucine,

• lysine,

• methionine,

• tryptophan,

• valine,

• leucine,

• threonine.

Animal proteins contain all essential and non-essential amino acids in optimal proportions, making them complete proteins.

Plant-based foods also contain both types of amino acids, but no single vegetable or legume offers the complete amino acid profile in ideal proportions. Therefore, if you’re on a vegetarian diet, it’s essential to consume a variety of plant foods throughout the day to ensure complete amino acid intake.

If you’re a physically active vegetarian—especially if you’re focused on building muscle mass—it’s important to properly combine food sources. In a single meal, combine grains (rich in methionine) with legumes (rich in tryptophan and lysine). This improves amino acid availability for muscle building.

The best sources of protein in a vegetarian diet (depending on the type) include: fish, eggs, dairy, legumes, nuts, and whole grains.

Can You Build Muscle Without Creatine?

Creatine is an organic compound naturally found in the human body. About 95% of it is stored in skeletal muscles. Around 1–2% of intramuscular creatine is converted into creatinine and excreted in urine. Therefore, the body needs about 1–3 grams of creatine daily, which is primarily obtained from meat—especially red meat—and fish (e.g., herring, salmon, tuna).

A regular diet provides about half of the daily creatine requirement. The rest is synthesized in the liver and kidneys from arginine and glycine. Vegetarians and vegans tend to have lower intramuscular creatine stores (90–110 mmol/kg of dry muscle mass) due to lower dietary intake.

In such cases, creatine supplementation can lead to a greater increase in muscle creatine levels. Supplementation improves intramuscular creatine concentration and may enhance performance and/or training adaptation (2).

Adequate creatine reserves in muscle tissue are particularly important for speed- and strength-based activities. They support recovery, prevent injuries, and have an anabolic effect, promoting faster muscle growth and strength.

Does this mean that people who eliminate meat from their diets can’t build muscle? Absolutely not! Muscle growth is not solely dependent on creatine intake but rather on the overall dietary balance.

Carbohydrates in a Vegetarian Diet – Which to Choose?

Athletes on a plant-based diet should first and foremost ensure adequate calorie intake. Insufficient energy intake in active individuals can impair performance. Remember that carbohydrates are the primary fuel for working muscles.

Recommendations for carbohydrate intake in athletes range from 4 to 12 grams per kilogram of body weight per day. When activity levels are low (under 60 minutes per day), the suggested intake is 3–5 g/kg. This increases to 5–7 g/kg with moderate activity.

Choose primarily whole grains as carbohydrate sources, as they also provide B vitamins, magnesium, and zinc. Around workouts, when there’s limited time between meals and exercise, opt for high-carb cereals or fruits. These provide quick energy without causing digestive discomfort during activity.

If your pre-workout meal is 1–2 hours before exercise, go for fruit smoothies, white pasta, white rice, or small-grain cereals with vegetables (3, 4).

Fats in a Plant-Based Diet

Fat requirements for athletes are similar to general population guidelines: 20–35% of total calories. Fat deficiencies are not commonly observed in vegetarian diets, but the type of fat consumed matters.

Due to the elimination of fish and seafood, special attention should be paid to omega-3 intake. These fatty acids must be obtained from food because the human body lacks the enzymes needed to synthesize them (5). Omega-3s are especially recommended for physically active individuals due to their anti-inflammatory and immune-supporting effects.

Omega-3 fatty acids include alpha-linolenic acid (ALA)—found in flaxseeds, flaxseed oil, soybean oil, canola oil, and walnuts—as well as DHA and EPA, found in fatty fish like herring, salmon, mackerel, sardines, anchovies, and tuna.

Fats are also a concentrated energy source and can help meet high energy demands without increasing food volume.

Plant-Based Diet and Nutrient Bioavailability

Athletes on vegetarian diets should pay close attention to their intake of key nutrients. Iron, calcium, and zinc are particularly important for physically active individuals.

Iron
Iron plays a vital role in oxygen transport and is positively correlated with physical performance. Physically active people must ensure adequate iron intake.

Meat products contain heme iron, which is highly bioavailable. Plant sources—like amaranth, lentils, quinoa, and buckwheat—contain non-heme iron, which is less efficiently absorbed. Vegetarian diets also tend to be high in compounds that inhibit iron absorption, such as phytates and oxalates.

Vegetarians should increase their iron intake by about 180% [American Dietetic Association]. To improve iron absorption, add vitamin C–rich foods and organic acids to meals. Also, avoid drinking tea and coffee with meals (5).

Calcium
Those who include dairy in their diet usually get enough calcium. Excluding dairy can increase the risk of deficiency and related issues like osteoporotic fractures. Calcium is also crucial for nerve signaling and muscle contractions. Its deficiency may impair physical performance.

Good plant-based calcium sources include: soy, dried figs and apricots, almonds, poppy seeds, tahini, kale, and beans. For athletes, calcium-rich mineral waters are also excellent. Keep in mind that calcium bioavailability can be reduced by oxalates, phytates, and dietary fiber.

Zinc
Zinc is involved in many enzymatic and metabolic processes and supports cell membrane stability and immune function. In athletes, it’s particularly noted for its role in testosterone synthesis.

Strength athletes especially should ensure sufficient zinc intake. Plant-based sources of zinc include legumes, nuts, and seeds. Due to the low bioavailability of zinc from these sources, vegetarians should increase intake by around 50%. Zinc absorption can be improved by pairing it with organic acids (e.g., citrus fruits, apples, apple cider vinegar) (5).

Vegetarian Diet for Athletes – Summary

A vegetarian diet can be a suitable nutritional model for athletes. It can meet the increased nutritional demands of physically active individuals.

Vegetarianism does not negatively affect athletic performance, muscle growth, or post-exercise recovery—provided that the diet is properly balanced, energy needs are met, and attention is given to nutrient bioavailability and supplementation when necessary.