Vegan Weightlifting: What Does the Science Say?
Many weightlifters think a vegan diet might be detrimental to their efforts because of the lower protein content of a typical vegan diet. Other weightlifters feel that a vegan diet enhances their training regimen by reducing fatigue and improving general health. Unfortunately, there are no studies looking directly at vegan weightlifters, but there is a fair amount of research that can be used to extrapolate to vegans.
While reading this article, keep in mind that weightlifting can be divided into two types:
- Bodybuilding to achieve the most noticeable muscles.
- Powerlifting to produce the largest amounts of strength.
- Vitamins and Minerals
- During Workouts
- After Workouts
- Carnosine and beta-Alanine
Carbohydrates, fat, protein, and alcohol all provide energy. Resistance training, exercises where muscles push or pull against some force, is used to develop and maintain muscular strength and requires an increase in energy above that of sedentary individuals. The amounts vary depending upon training regimen, as well as other factors, including exercise efficiency, gender, non-exercise habits, and genetics. Because of the variation in needs, there is no one easy formula for caloric requirements; it is a matter of experimentation.
It is important to note that not eating enough calories to meet needs will tend to reduce muscle mass. Eating adequate calories spares muscle protein that would otherwise be used for energy. For a general ballpark figure, novice male weightlifters increased muscle mass and size, and lowered body fat, on a diet of about 18 calories/lb of body weight per day (3240 calories/day for a 180-lb person) (1). In another study, highly trained male bodybuilders ate 22.7 calories/lb (4,086 calories/day for a 180-lb person) (2).
Depending on the source, protein needs among weightlifters are reported at values equal to the Recommended Dietary Allowances (RDA) to values as high as four times the RDA (Table 1). During the 1800s, it was believed that protein was the main fuel used during exercise. But work in the early part of the 1900s indicated that exercise did not change protein needs and, until the 1970s, was accepted without further research (3). Recently, there has been more research on protein requirements of athletes, with varying interpretations.
|Table 1. Suggested Protein Intakes|
|g/kg of body weight||g/lb of body weight||g/day for a 180 lb person|
|RDA for Adults||
|RDA for 14-18 year olds||0.85||0.39||70|
|Tarnopolsky et al.2||1.1 to 1.5||0.5 to 0.68||90 to 123|
|Lemon et al.1||1.65||0.75||135|
|American Dietetic Association35||1.2 to 1.7||.55 to .77||98 to 139|
|Table 1 lists protein intakes suggested by various sources. Protein needs are normally stated in grams of protein per kilogram of healthy body weight. For the reader's convenience, the numbers are translated into grams of protein per pound of healthy body weight. As an example, grams of protein per day for a 180 pound person are listed.|
Determining how much protein a person needs is often done by using nitrogen balance studies. Nitrogen is a component of amino acids, the building blocks of protein, and can serve as a marker for protein metabolism. Positive nitrogen balance means that the person is taking in more nitrogen than he or she is excreting, and is therefore using that nitrogen to build muscle. Negative nitrogen balance means more nitrogen is being excreted than consumed, and thus muscle is breaking down. When looking solely at athletic performance, nitrogen balance is an indirect method of measuring protein needs; what really matters is whether the person increases muscle mass, strength, or speed.
Two studies are particularly relevant. Lemon et al. studied 12 men starting an intensive weight training program of 1.5 hours, six days a week (1). They compared one month of supplementing with carbohydrates (on a diet of 1.4 g/kg of protein per day) to one month of supplementing with protein (for a total of 2.6 g/kg of protein per day) for the same people. They determined that a protein intake of 1.6 to 1.7 g/kg was needed to achieve nitrogen balance. However, muscle size and strength increased the same amount on both regimens. The authors thought that extra amino acids for the muscle-building during the carbohydrate phase were coming from amino acid pools found in the digestive tract, kidneys, or liver. These sources are small and will eventually be depleted.
The second study was conducted by Tarnopolsky et al. on six lacto-ovo vegetarian bodybuilders who had been training intensively for at least three years (2). The bodybuilders normally ate 2.77 g/kg of protein. Upon reducing their protein intake to 1.05 g/kg, the group remained in nitrogen balance and changes in lean (non-fat) body mass did not occur. Two individuals, however, were found to have a negative nitrogen balance while eating 1.05 g/kg of protein. These results indicated that protein needs for the majority of advanced bodybuilders are fairly close to 1.05 g/kg but that some may have higher requirements.
Taken together, these studies on a small number of athletes imply that protein needs (per body weight) may be greater in the beginning stages of training (when muscles are making larger increases and protein is deposited) than when muscle mass has plateaued.
The Food and Nutrition Board, which sets the RDA, reviewed Lemon et al.'s study and others and concluded there is not sufficient evidence to support the idea that resistance training increases the protein RDA of .80 g/kg for healthy adults. They state, "Therefore, the available data do not support the conclusion that the protein requirement for resistance training individuals is greater than that of nonexercising subjects (34)."
Some vegan health professionals have recommended slightly higher protein intakes (.9-1.0 g/kg of body weight) than the RDA for vegans in general (5, 6). However, the Food and Nutrition Board has said that if complementary sources of protein are used (generally mixing beans and grains throughout the day), vegetarians' protein needs are no greater than non-vegetarians (4). It should be noted that the RDA for protein has a margin of safety such that many sedentary adults meeting the RDA will actually get more protein than they need. Considering the information reviewed above and the lack of other specific research, it seems reasonable to conclude that the protein needs of most vegan bodybuilders are somewhere between .8 and 1.5 g/kg (.36 and .68 g/lb) of body weight.
On average, vegans consume about .9 g of protein/kg of body weight and obtain 13 percent of their energy from protein (7). Thus, if a vegan eats 18 calories/lb, which is on the lower end for serious weightlifters, he or she will naturally consume 1.3 g of protein/kg of body weight, likely meeting protein needs. However, if more carbohydrates, such as pasta, are primarily chosen to increase caloric intake, the percentage of protein may be less.
For this reason, vegan weightlifters should make an effort to also select high protein foods. Legumes, soyfoods, quinoa, and wheat gluten (seitan) are the typical vegan foods highest in protein. It is also possible for vegans to take a protein supplement, though this is not necessary. If vegans do supplement, Naturade makes a number of vegan protein supplements, including a soy-free protein supplement for those allergic to soy or who do not want more soy in their diet.
Please see the article Where Do You Get Your Protein for a list of high protein plant foods.
Based on studies of endurance athletes, some researchers believe that fat is an important part of the athlete's diet. Diets that are too low in fat (15 percent or less fat) may compromise immunity, reduce intramuscular fat stores (which could spare muscle protein), and reduce energy intake (8). While this has not been studied in bodybuilders, the novice bodybuilders in Lemon et al.'s study received about 31 percent of their calories from fat and succeeded in increasing strength and muscle size (1). Average fat intake for vegans is about 28 percent of calories (9). Higher fat intakes might also reduce the chances of irregular menstrual cycles in women caused by low body fat.
All vegans should pay attention to omega-3 fatty acid intake; you can read more about that in the article Omega-3 Fatty Acid Recommendations for Vegetarians.
Carbohydrates are the major fuel used during resistance exercise (3). Some researchers recommend 6 g of carbohydrate/kg of body weight (2.7 g/lb) daily, or about 55 to 60 percent of total intake (10). Vegan weightlifters who meet energy requirements and stay close to the protein and fat recommendations listed here would automatically eat enough carbohydrates.
When food intake increases, as it should on a weightlifting regimen, vitamin and mineral intake will also naturally increase. Vitamin or mineral intake in excess of the RDA has not been studied in weightlifters. Vegan weightlifters should pay attention to the typical nutrients that are recommended for all vegans (mainly vitamin B12, calcium, iodine, and vitamin D), but there is no evidence that any of these nutrients are needed in larger amounts than what would normally be consumed in a typical, varied vegan diet.
Female bodybuilders, especially those who experience amenorrhea (cessation of menstrual periods), should pay careful attention to getting enough calcium and vitamin D. The RDA for adults is 1,000 mg for calcium and 5 micrograms (200 International Units) for vitamin D. Some health professionals recommend a multivitamin of 50 to 100 percent of the RDA for all people. That could be more important for people restricting their caloric intake.
Carbohydrate supplementation during weight training may be beneficial for promoting higher quality training and perhaps improving muscle gain. Ingesting carbohydrates during resistance exercise has been shown to increase the number of sets and repetitions before exhaustion (10). For example, one good vegan source is R.W. Knudsen's Recharge (7 percent sugar), a sports drink without artificial ingredients that is available at most natural foods stores. Also, fruit juice diluted at a rate of 1 part juice to 1 part water will provide a sugar content comparable to sports drinks.
Doi et al. found that eating a supplement of protein (10 g), carbohydrate (7 g), fat (3 g), and a third of the RDA for vitamins and minerals immediately after, versus 1.5 hours after light resistance exercise, may reduce nitrogen losses and increase resting metabolic rate (indicating that muscle mass may be preserved) (16).
Creatine (also known as creatine monohydrate) is the only nutritional supplement that has been consistently shown to improve strength and muscle mass. The main benefit of creatine is thought to be due to its effect on reducing fatigue during repeated, short bursts of intense exercise (such as weightlifting, sprinting, soccer, rugby, and hockey (17). Lower fatigue during sprinting and weightlifting means increased training and greater results (17).
Creatine is a component of phosphocreatine (PCr). PCr provides energy during short bursts of powerful exercise, by providing a phosphate for the production of adenosine triphosphate (ATP), which is the quickest source of energy in skeletal muscle. Depletion of PCr in muscle is associated with fatigue during such exercise (18).
Creatine can be synthesized in the body. It is also supplied in the diet by meat and fish. Supplementing with creatine has been shown to increase performance (18, 19) especially in people whose creatine levels in muscle were initially on the lower side of normal (17).
Generally, a daily total of 20-30 g of creatine, broken up in smaller doses over the course of a day and taken for five to six days, has been shown to increase performance (17). There appears to be no benefit to taking this dose for longer than six days (17). After the initial "loading" phase, 2 g/day maintains creatine levels for at least one month (17). Some researchers suggest taking creatine only every other month to maximize its effects (10).
Vegetarians have lower levels of creatine in their blood, urine, and red blood cells (18, 21) and muscle tissue (33), and there have been three studies of creatine supplementation in vegetarians that have measured strength or muscle size outcomes:
In a 1997 Belgium study of vegetarians, creatine supplementation did not improve power output (22).
In a 2000 Swedish study, vegetarians and meat-eaters took 7 g of creatine three times a day for six days. The vegetarians and meat-eaters improved their average power output after creatine supplementation, but only the meat-eaters significantly increased their peak power output (18).
A 2003 study from Canada was conducted on 19 vegetarians (including 3 vegans) and 30 non-vegetarians. Participants had been recreational athletes, all with some resistance training but not a lot (33).
For the 7 day loading phase, subjects were given 0.25 g of creatine per kg of lean tissue mass (average of 16.8 g per day). For the 49 day maintenance phase, they were given 0.0625 g per kg of lean tissue mass (average of 4.2 g per day). They were put through an intense weight training routine, focused mostly on the upper body.
Subjects on creatine increased muscle mass more than those receiving placebo, with the vegetarians on creatine increasing most of all (2.4 kg of lean tissue vs. 1.9 kg for non-vegetarians using creatine). The maximum bench press amount increased 15.9 kg for those taking creatine and only 8.7 kg for those taking a placebo. Maximum leg press increases did not vary between the supplementation or diet groups.
Vegetarians on creatine most greatly improved their ability to do work on a knee flexion/extension machine than other groups. Vegetarians had greater increases in muscle concentrations of total creatine and phoshocreatine. Supplemented groups had much higher training volumes. ATP concentrations did not vary among groups.
Based on these three studies, it seems reasonable to conclude that vegetarian weightlifters can improve performance by taking creatine.
The loading phase for vegetarians and non-vegetarians is probably similar, because their dietary intake is negligible compared to the amounts supplemented. However, because the average meat-eater consumes 1-2 g of creatine a day, 30 percent of which is destroyed by cooking (23), the maintenance phase for vegetarians may need to be as high as 3.4 g/day.
Consuming powdered creatine with a sugar solution, such as a sports drink or fruit juice, increases the rate at which muscles absorb the creatine (17).
Supplement companies say that creatine supplements are made without using animal derivatives (24).
In the short term, creatine supplementation does not appear to cause problems in people without a history of kidney problems. One study looked at markers of liver and kidney function after five days of 20 g/day and found no problems; similar studies have confirmed these results (17). No side effects have been found in people taking 20 g/day for up to five weeks (19). However, there are some anecdotal reports of muscle cramps and tears from creatine supplementation (19).
The long-term effects of creatine supplementation have not been studied, but there have been no reports of long-term problems. British weightlifters have used creatine for three to five years without problems.
There is one case of a person with a history of kidney disease whose kidney function further deteriorated after taking creatine. Thus, people with kidney disease are warned against taking the supplement (18).
While it is not clear that vegan weightlifters must use creatine to achieve maximum results, it appears to be safe in the amounts that have been studied, and it could possibly improve performance.
Carnitine (also known as L-carnitine and acetyl-L-carnitine) is an amino acid that is made in the liver and kidneys. It is also found in meat and dairy products (25), but there is very little found in plant foods. Carnitine is needed for the burning of most fats. Thus, carnitine supplements are promoted by supplement companies for weight loss. However, evidence shows that most people (among the non-vegetarian population) who take the supplements do not lose weight (26). Effects of carnitine supplementation on weightlifting or bodybuilding have not been studied.
Carnitine levels tend to be lower in people eating lower fat, higher carbohydrate diets (27). When intake of carnitine is low, less carnitine is excreted. Vegans and lacto-ovo vegetarians have lower blood levels of carnitine (21, 27-29, 36). Researchers in one study did not think the lower carnitine levels of vegetarians were unhealthy (27). It is not known if the lower levels have any bearing on athletic performance. A 2011 study showed vegetarians' muscles to have a lower ability to absorb carnitine than omnivores. Vegetarians also excreted less carnitine than omnivores, indicating that other tissues or muscles that were not tested were possibly absorbing the carnitine (36).
Non-vegetarians typically eat 100-300 mg of carnitine per day (30). It would appear safe, therefore, for vegans to take 100-300 mg/day if they choose to do so. In one study, supplementing with 120 mg/day for two months did not significantly increase plasma carnitine levels in 11 vegans, while urinary carnitine excretion did increase (31). This implies that the subjects were urinating most of the extra carnitine out, though it is possible that they were utilizing some of it.
There are side effects to large amounts of carnitine. In one study, 2,000 mg of carnitine, twice daily, was associated with nausea and diarrhea in 5 of 18 people (26).
Solgar's carnitine supplement is made through yeast fermentation of beet sugar (32).
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