Vegetarianism, veganism, raw foodism – these are trends of modern society. The reasons why people change their dietary habits are completely different and we are not interested in them at all.
There are supporters of vegetarianism in sports as well. Most often, people become vegetarians because it is believed that excluding animal products from the diet increases endurance and is beneficial for health.
In this article, we will discuss the pros and cons of vegetarianism in sports, focusing on the risks. The source of information is the Encyclopedia of Sports Medicine edited by Ronald J. Maughan.
Main thoughts:
A Brief History of Vegetarianism in Sports
The Strongmen of Ancient Greece Were Meat-Eaters…
A well-known fact is that the strength athletes of Ancient Greece were all meat-eaters. They consumed a lot of meat. They believed that one could only become strong and gain muscle mass by consuming animal protein.
One example is Milo of Croton, a legendary Greek athlete who, according to legend, trained by carrying a calf on his shoulders: as the calf grew (= the weight increased), so did his muscle strength. He consumed an enormous amount of meat.
It is quite possible that the amount of protein in Milo’s diet was excessively high, but that did not prevent him from winning at 5 Olympics 2.
This same concept of the necessity of consuming a large amount of animal protein for success in sports was promoted in the early 1800s by one of the most famous chemist-physiologists of his time, Liebig 3. He was convinced that protein was the main substance for building muscles.
Despite the fact that in the mid-1800s Atwater disproved Liebig’s hypothesis, myths about the benefits of a huge amount of protein for muscle mass gain still circulate in gyms today…
The athletes of Ancient Greece were all meat-eaters. The hypothesis that athletes need a huge amount of protein was disproven by scientists in the 19th century, yet the myth “the more protein, the better” remains popular in the world of sports (especially bodybuilding)
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The History of the Emergence of Vegetarianism
The history of the emergence of vegetarianism also begins in Greece. The first vegetarian was Pythagoras, a Greek mathematician, the creator of the well-known Pythagorean theorem.
Until the mid-19th century, vegetarians referred to themselves as “Pythagoreans” 4.
Vegetarian athletes have always attempted to prove the benefits of vegetarianism, with one such fact recorded in the mid-19th century.
In the second half of the 1800s, the London Vegetarian Society organized a club for vegetarian athletes and cyclists to hold competitions against meat-eaters. In most cases, vegetarians indeed won 5.
Thanks to their victories, many other athletes also turned to vegetarianism.
One such competition was the Berlin-Vienna bicycle race in 1893, covering a distance of 599 km. The first two winners were… vegetarians 6.
Over the next 20 years, vegetarians repeatedly proved their ability to compete on par with meat-eaters in endurance sports.
After that, scientists began to get involved in researching the benefits of vegetarianism in sports.
In 1907, scientist Fischer conducted the following experiment involving student-athletes. All participants consumed different diets, some meat-based, some vegetarian.
Each of them underwent the following endurance test: the time of holding their arms in a horizontally extended position was measured, as well as the maximum number of deep squats.
Result: vegetarian athletes performed better on the task than meat-eaters.
Another interesting experiment involving a 48-year-old Olympic cyclist was conducted in 1934. The cyclist had been a vegetarian for 23 years.
The essence of the experiment was that for 4 weeks he was fed a vegetarian diet with varying amounts of protein. After that, various indicators were measured during an 8.5-hour cycling session.
Result: higher speed indicators were associated with a greater protein content in the diet, and plant-based protein sources were linked to higher performance.
Vegetarian athletes have repeatedly proven their ability to compete on par with meat-eaters, especially in endurance sports.
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Vegetarianism in Sports Today
Modern understanding by scientists of the relationship between vegetarianism and sports is revealed in the following quote 1:
“Unfortunately, after many years of research, the effect of excluding animal products from the diet on sports performance is unclear.
Most recent studies on vegetarianism in sports have focused on health benefits rather than impacts on athletic performance.“
There is insufficient data on the compatibility of vegetarianism and sports for definitive statements, but it is clear that athletes on a vegetarian diet have a higher risk of deficiency in certain macro and micronutrients, and to avoid this, they need to approach diet planning more carefully.
The lack of any micro and macro elements inevitably affects sports performance.
“The benefits of vegetarianism for health and potential increases in sports performance are not related to the absence of meat in the diet, but to the fact that vegetarians consume more plant-based foods.”
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Scientific research on the benefits of vegetarianism in sports
The question of the benefits of vegetarianism in sports is hardly researched these days, despite the popular belief that vegetarianism provides clear advantages in some sports.
However, there are some very interesting facts worth noting.
One such fact is related to the Tarahumara tribe from the mountainous regions of Mexico.
Its members are known for their supernatural endurance as ultra-distance runners 7. And all of them are… vegetarians. Their diet contains almost no meat, and they can run up to 320 km 7.
The basis of their diet consists of corn, legumes, and squash/zucchini.
Approximately 94% of the protein in their diet comes from plant-based foods and only 6% from animal sources. They consume 2-3 eggs per week and occasionally small portions of meat, fish, dairy products, and lard.
Overall, their diet is predominantly plant-based, rich in nutrients, and does not lead to deficiencies in macro or microelements.
Here’s another example. In 1986, scientist Hanne and colleagues measured various indicators of athletic performance in vegetarian and meat-eating athletes of different ages and genders.
The parameters they measured included: anthropometric data, lung and heart function, aerobic and anaerobic capacity, and blood composition. As a result, NO significant differences were found between the two groups.
This result in this and similar studies can be explained by many reasons, the most important of which is: vegetarianism does not imply a single clear diet, i.e., it is unclear what specific type of vegetarianism the participants in the experiment adhered to.
Vegetarians can equally be:
- those who eat only raw vegetables and fruits;
- lovers of baked goods, sweets, cola, and chips;
- those who eat 10 eggs a day, washed down with kefir.
There is very little scientific research on the benefits of vegetarianism in sports, and they are contradictory. Ultra-distance runners from the Tarahumara tribe are vegetarians. Some studies suggest there is no benefit at all.
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Types of vegetarianism: veganism, vegetarianism, lacto-vegetarianism, semi-vegetarianism. What is the difference?
There is a wide variety of types of vegetarianism: starting from veganism, which completely excludes animal products, to various branches that allow the consumption of certain types of animal proteins (lacto-vegetarianism, ovo-vegetarianism, lacto-ovo-vegetarianism, etc.).
In general, vegetarianism refers to a large number of dietary styles: from consuming only plant-based foods to limiting certain types of animal products or the frequency of their consumption 8.
That is why the statement “I am a vegetarian” is somewhat meaningless, as it carries almost no information about what exactly this particular person eats.
In my life, I have encountered many vegetarians whose diet consisted mainly of sweets (cookies, cakes, candies). A vegetarian can even be someone who does not eat meat but regularly consumes alcohol in large amounts…
That is why studies on the benefits of vegetarianism on real vegetarians are not very informative if the diet is not meticulously tracked.
| Types of vegetarianism | |
|---|---|
| Type of vegetarianism | What can/cannot be eaten |
| Semi-vegetarianism | Some types of animal products can be eaten (but not all): meat, poultry, fish and seafood, eggs, dairy products |
| New vegetarianism | The diet is mainly based on plant products, some types of animal products can be eaten, but the importance of their organic origin is especially emphasized: they should not be processed, enhanced, or refined and must be grown in natural conditions |
| Pescatarianism | Red meat is excluded, but fish is allowed |
| Lacto- and ovo-vegetarianism | What can be eaten: dairy products and eggs What cannot be eaten: meat, poultry, fish, seafood |
| Ovo-vegetarianism | What can be eaten: eggs What cannot be eaten: dairy products, meat, fish and seafood, poultry |
| Strict vegetarianism or veganism | Any types of animal products are excluded: meat, fish, dairy, eggs. Only plant-based food can be eaten |
| Macrobiotic diet | All types of animal products are prohibited. Plant-based products should only be natural, organic, unprocessed, and unrefined. Sometimes, even types of liquids are limited. Various types of soy products and seaweed can be consumed. |
| Raw foodism | One can eat exclusively raw or dried fruits, vegetables, nuts, seeds, honey, and plant oils. |
There is a wide variety of vegetarianism. The statement “I am a vegetarian” is meaningless. Even someone who does not eat meat but consumes alcohol or lives on sweets washed down with soda can call themselves a vegetarian.
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Cons of vegetarianism: deficiencies in macro and micronutrients
Sports do not exclude vegetarianism: gaining muscle mass in bodybuilding or improving speed and endurance in running is possible on a plant-based diet… but only if one consumes an adequate amount of diverse plant foods 9.
There are several micronutrients and macronutrients for which the risk of deficiency among vegetarian athletes is very high, and they need to be given close attention when planning the diet. The most important of these is protein.
1 Vegetarian athletes have an increased risk of PROTEIN deficiency
Lacto-ovo-vegetarians and ovo-vegetarians usually obtain enough high-quality protein, and the risk of deficiency is low for them.
The risk of protein deficiency is high among vegan athletes, who do not consume any animal products at all.
The problem is that plant protein is generally incomplete, meaning it lacks one or two amino acids (they are either completely absent or present in very small amounts).
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Where can a vegetarian get protein?
Since individual plant products do not contain certain amino acids, scientists recommend that vegetarian athletes supplement their protein sources by combining different products.
For example, grains contain very little of the amino acid lysine, while legumes are characterized by a slight deficiency of sulfur-containing amino acids. If they are combined, a high-quality protein can be obtained.
The figure below shows various combinations of incomplete proteins that result in a complete one. It also indicates that combining an incomplete plant protein with a complete animal protein also yields high-quality protein – the principle of “half” types of vegetarianism (lacto-, ovo-, pesco-).
The concept of combining different types of incomplete proteins to obtain complete ones: products lacking certain amino acids are complemented by others that contain these amino acids in sufficient quantities.
The risk of protein deficiency is high among vegan athletes. To obtain complete protein with all amino acids, vegans are recommended to combine various complementary plant protein sources.
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How much protein do vegetarian athletes need?
In the previous section, we touched on the issue of the quality of plant proteins.
For vegetarian athletes, it is important to consume sufficient amounts of protein.
The protein norm for vegetarians and meat-eaters is the same and is determined by the type of sport. For strength sports (bodybuilding, weightlifting) and those requiring endurance (running, cycling), it is 1.4-1.8 grams/kg of body weight per day. In chess – less 😉
At the same time, it is important to consume enough carbohydrates and fats for energy; otherwise, the body will use protein for this purpose. See Nutrition principles for gaining muscle mass: 7 recommendations from experts.
However, in the case of vegetarianism, scientists and doctors recommend slightly increasing the specified protein norm, as plant protein is absorbed worse and has lower quality.
And one more thing.
It was previously a common belief that every meal must contain all amino acids. Now scientists are convinced that it is important to have a sufficient amount of all amino acids throughout the day, and the exact timing of their intake does not matter much 1.
They provide the following explanation:
“Scientific research clearly indicates that the liver acts as a controller-supervisor for adequate protein intake: if any amino acid is lacking in the diet, the liver breaks down its own proteins to compensate for the deficiency. When there is again enough protein and amino acids in the diet, the liver restores its storage.”
The protein norm for vegetarian athletes is 1.4-1.8 g/kg of body weight. The presence of all amino acids in every meal is not necessary: it is important to have enough of them throughout the day.
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2 Vegetarians have an increased risk of vitamin B12 deficiency
Vitamin B12 deficiency is very likely especially among strict vegetarians (vegans) on an exclusively plant-based diet, as its sources are exclusively animal products.
Studies confirm that the level of vitamin B12 in the blood of vegetarians is significantly lower compared to omnivores 10, with a difference of ~30%, sometimes reaching 50-60% 11.
The deficiency of vitamin B12 is primarily characteristic of vegans, who do not consume any animal products at all. Cases of deficiency among lacto-ovo-vegetarians are very rare, as milk and eggs contain it in sufficient quantities.
Vegan athletes are recommended to consume foods fortified with vitamin B12 or to take it as a supplement.
The analogs of this vitamin found in algae, spirulina, nori, or fermented soy products are not of great value to humans.
The symptoms of vitamin B12 deficiency are as follows:
- numbness and tingling in the hands and feet;
- weakness, fatigue;
- coordination disorders;
- a range of mental disorders, including disorientation, depression, and memory loss.
Alcohol, tobacco, and medications (containing antacids, neomycin, colchicine, and aminosalicylic acid) can increase the degree of vitamin B12 deficiency, as they hinder its absorption. This applies to both omnivorous athletes and vegetarians.
The risk of vitamin B12 deficiency is high among vegans and virtually absent among lacto- and ovo-vegetarians. Alcohol and tobacco increase the degree of deficiency in both vegetarians and omnivores.
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3 Vegetarians have an increased risk of IRON deficiency
Athletes who consume red meat have a lower risk of iron deficiency.
Overall, the amount of iron in meat is not very high and not very low; however, the bioavailability (or absorption) of iron from meat is significantly higher than from plant products.
There are two types of iron: heme iron and non-heme iron. The former is found in meat, fish, and poultry and is better absorbed than the latter, which is found in grains, vegetables, and fruits.
The absorption of iron from different products ranges from 3%-35%, depending on the type of iron (heme/non-heme), the presence of vitamin C, and the amount of iron in the body.
Iron is involved in the synthesis of hemoglobin (a component of red blood cells responsible for transporting oxygen in the blood), myoglobin (responsible for transporting and storing oxygen in muscles), collagen, and various neurotransmitters. It is necessary for immune function and also participates in detoxifying toxins in the body 12.
Since iron is responsible for delivering oxygen to all organs and tissues, including muscle, it is critically important for athletes to have an adequate intake of it. From a practical standpoint, its deficiency manifests as a decrease in athletes’ endurance.
There is an even higher risk of iron deficiency among female athletes and vegetarians, as a significant amount is lost during menstruation.
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Recommendations for vegetarian athletes to increase iron intake in their diet
As mentioned above, iron is present in sufficient quantities in meat in a form that is well absorbed.
Lacto-ovo-vegetarianism is NOT a solution to iron deficiency, as dairy products and eggs contain very little of it.
To avoid deficiency, vegetarian athletes can include green leafy vegetables (such as spinach), legumes, and iron-fortified products in their diet.
Strangely enough, metal kitchen utensils are also a source of iron: when acidic foods are cooked in such cookware, some iron transfers from the cookware to the food.
The risk of iron deficiency is high for all vegetarian athletes (regardless of the type of vegetarianism) who exclude meat. Iron from plant foods is absorbed poorly.
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4 Vegetarians have an increased risk of ZINC deficiency
Zinc is the next mineral for which the risk of deficiency is very high among vegetarian athletes.
The best sources of zinc are meat, dairy, and seafood (especially oysters). The likelihood of deficiency is lower among those types of vegetarianism that do not exclude these products.
For vegans, the main sources of zinc are whole grains and products made from them; however, its absorption may be hindered by fitates 13.
The impact of plant phytates on mineral absorption is detailed in the material on the benefits/harms of soy and soy protein isolate.
Zinc is present in almost every tissue of the body and is used in the synthesis of about 100 enzymes. It also plays a role in protein creation in the body and is a component of the insulin molecule.
Research indicates that engaging in sports contributes to increased zinc excretion from the body, raising the risk of deficiency 14-17.
Zinc deficiency can develop due to inadequate amounts in the diet, poor absorption, increased losses during sports activities, and redistribution of its content in the body.
Studies confirm that athletes who are vegetarians have lower levels of zinc in their bodies.
According to one study, vegans and lacto-vegetarians consume about 2 times less zinc than recommended 18.
Similar values were obtained in another study: 33% of semi-vegetarians, 24% of lacto-ovo-vegetarians, and 18% of omnivores had zinc levels significantly below normal 19. It was also noted that there is a very high concentration of phytates in the body.
The main reason for zinc deficiency identified by scientists is the low zinc content in the foods consumed across all groups.
The risk of zinc deficiency is high for all types of vegetarianism, but especially for vegans. Engaging in sports enhances the “washing out” of zinc from the body. Its absorption from plant products is hindered by phytates.
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Recommendations for vegetarian athletes to increase zinc intake in their diet
Sources of zinc for vegetarians include the following natural products: oysters, crabs, shrimp, wheat germ, and legumes. Nuts and whole grains have slightly lower biological value.
During the processing of plant products (refining), zinc is removed from them. Thus, premium flour is a poor source of zinc.
5 Vegetarians have an increased risk of CALCIUM deficiency
In the diet of vegetarians who do not consume dairy products (strict vegetarians and vegans), there is a high risk of calcium deficiency.
As with iron and zinc, the absorption of calcium is hindered by substances found in plants: phytates, oxalates, fiber 20,21.
Phytates (or phytic acid) are found in oat flour and other whole grains, while oxalates are present in beets, spinach, and leafy greens.
It is evident that the highest risk of calcium deficiency is among vegans, who obtain most of their dietary calcium from leafy greens and whole grain products.
In addition, a strict vegan diet may also lack sufficient vitamin D, further impairing calcium absorption.
In a curious anthropological study of ancient burials in the Canary Islands, a large prevalence of osteoporosis was found in 117 skeletons. The bones contained very low concentrations of iron, zinc, and calcium, and the bone mass was significantly below normal.
Researchers note that during that period, the diet of the Canary Islanders was predominantly vegetarian with low protein content.
Scientists recommend that those vegetarians who do not consume dairy products should definitely supplement their diet with plant-based foods rich in calcium or calcium-fortified foods.
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Recommendations for vegetarian athletes to increase calcium intake in their diet
Good sources of calcium include dark leafy green vegetables (spinach, broccoli), low-fat milk, Romano cheese, Swiss cheese, sardines, and canned salmon.
The absorption of calcium from leafy greens is hindered by oxalic acid; the effect of oxalates on absorption is significantly weaker in cabbage, turnips, and mustard greens.
The best source of calcium is low-fat milk.
A good alternative is calcium-fortified products: juices, bread, breakfast cereals, breakfast bars, and soy cheese (tofu) when made from calcium carbonate (usually indicated on the label).
The risk of calcium deficiency is high among vegetarians who do not consume dairy products, especially vegans. Its absorption from plant foods is hindered by phytates, oxalates, and fiber.
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The downside of vegetarianism in sports: impact on hormones
The impact of vegetarianism on hormones in female athletes
Vegetarianism is associated with a lower likelihood of breast, prostate, and uterine cancer in women.
However, it leads to a decrease in estrogen levels in the blood, which can affect the regularity of menstruation in women and also lead to a decrease in bone density.
What is the danger of menstrual irregularities?
According to scientists, menstrual cycle disturbances are directly related to a decrease in bone density, meaning they become more fragile 22.
Studies indicate that among inactive female vegetarians, differences in bone density compared to omnivores are virtually absent. The at-risk group is only female athletes. Scientists strongly recommend that they additionally consume calcium.
The likely cause of hormonal disruption is the isoflavones or phytoestrogens found in plants, which have a weak estrogenic or anti-estrogenic effect.
Isoflavones are particularly abundant in soy; they are also found in some grains, seeds, and nuts. Once ingested, they are converted by the intestinal microflora into a compound similar to the female sex hormone estrogen, which negatively affects its natural secretion.
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Overall, scientists have observed that fatty foods positively influence the level of female sex hormones, while fiber negatively affects it 23: when the diet is high in fiber, more estrogen is excreted along with feces.
Researchers state that the regularity of menstruation in women is determined by the amount of protein and cholesterol in the diet: the higher they are, the more regular the cycle 24. Conversely, irregular menstruation is associated with increased amounts of fiber and magnesium.
In one study, researchers compared the diets of female athletes with menstrual cycle disorders (82% of foods in their diet were plant-based) and those without disorders (13% of foods in their diet were plant-based) and found that women with regular cycles consumed five times more meat and significantly more fat 25, and their caloric intake was also significantly higher 26.
The Impact of Vegetarianism on Hormones in Male Athletes
There are very few studies on the impact of vegetarianism on hormones in men.
In one of them, it was shown that vegetarians, who consume significantly more coarse food with fiber, have a significantly lower level of testosterone in the blood compared to omnivores 27.
Vegetarianism affects the levels of sex hormones in the bodies of men and women. However, one of the main reasons is isoflavones or phytoestrogens. In male vegetarians, testosterone levels are generally lower, while in women, estrogen levels are lower.
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Recommendations from Scientists for Vegetarian Athletes
Today, there is much discussion about the health benefits of vegetarianism and very little about its impact on athletic performance. Vegetarianism and sports is a poorly researched topic.
It is obvious that vegetarian athletes must carefully plan their diet to avoid nutrient deficiencies, which would otherwise negatively impact their athletic performance.
Vegetarian athletes typically consume significantly more energy from carbohydrates. This is necessary to replenish glycogen stores (energy), especially in sports that require endurance.
Depletion of glycogen stores in muscles leads to chronic fatigue and reduces performance. During long and intense training sessions, it is important to eat foods rich in carbohydrates.
Scientists are concerned about the impact of a vegetarian diet on hormones, which can lead to menstrual cycle disruptions and bone fragility in female athletes.
Vegetarian athletes should be aware of potential nutrient deficiencies and strive to compensate for missing nutrients (especially protein, vitamin B12, zinc, calcium, iron).
Before any dietary experiments, it is important to consult with a sports dietitian.
It is not recommended to experiment with vegetarianism in sports during adolescence, as the body is still developing and active growth is ongoing. Nutrient deficiencies during this time are particularly dangerous (read my story in the article about protein deficiency).
Veganism in sports is acceptable only if the athlete is ready to fully immerse themselves in the issue and understand how to combine plant-based foods and in what quantities to consume them to ensure a balanced diet.
When planning any type of vegetarian diet, it is important to ensure variety in food and to monitor that the overall caloric intake is sufficient.
In addition to this, the American Dietetic Association provides the following recommendations for vegetarians:
- minimize the intake of low-nutrient foods (sweets, fatty foods)
- use whole grain products (not enriched, refined) or enriched grain products;
- consume a wide variety of vegetables and fruits;
- if the vegetarian diet allows for dairy products, it is better to choose low-fat options;
- limit the number of eggs to 3-4 per week;
- vegans should definitely consume additional vitamin B12 from fortified cereals or soy products. If the athlete primarily trains indoors, it is also important to take additional vitamin D.
