VEGETARIAN JOURNAL

Vegetarian Journal 2003 Issue 4

Vegan Weightlifting: What Does the Science Say?

By Jack Norris, RD

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 weight- lifters, 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:

Energy

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. Paying attention to hunger signals can be a good guide in knowing whether you are eating enough 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

Protein

Depending on the source, protein needs among weight-lifters 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.

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 treatment 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 no sufficient evidence to support that resistance training increases the protein RDA of .80 g/kg for healthy adults.

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 recently 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.

The largest study of vegans to date shows that they 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 seems to be on the lower end for serious weight-lifters, 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, and wheat gluten (seitan) are the typical vegan foods highest in protein (Table 2). It is also possible for vegans to take a protein supplement, though this is not necessary. If vegans do supplement on occasion, 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. Most health foods stores can order these if they do not carry them.

Table 1: Suggested Protein Intakes

 

g/kg of
body weight

g/lb of
body weight

g/day for a
180 lb person

RDA for Protein4

    Adults

0.80

0.36

65

    14-18 year olds

0.85

0.39

70

Tarnopolsky et al.2

1.1

0.5

90

 

1.5

0.68

123

Lemon et al.1

1.65

0.75

135

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.

Table 2: High Protein Plant Foods

  Serving Protein (g)
Wheat Gluten (Seitan) 3 oz. 22.5
Tofu 1/2 cup 10-20
Veggie Dog/Burger 1 6-18
Cooked Soybeans 1/2 cup 14.3
Texturized Soy Protein 1/2 cup 11
Soymilk 1 cup 5-10
Cooked Lentils 1/2 cup 8.9
Peanut Butter 2 Tablespoons 8
Cooked Chickpeas 1/2 cup 7.5
Sunflower Seeds 2 Tablespoons 5

Fat

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 body- builders, 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 Higher intakes might also reduce the chances of irregular menstrual cycles in women from low body fat.

Average fat intake for vegans is about 28 percent of calories.9 Some weightlifters try to avoid fats to lose body fat, but this is inadvisable for vegans who already eat relatively lowfat diets. A good estimate of optimal fat intake for vegan weightlifters is about 20 to 28 percent of calories.

Fried foods and hydrogenated oils (such as in many margarines) should not be used to increase fat intake. They have a high trans-fatty acid content, which increases the risk of heart disease. Avocados, nuts, flaxseed oil, olive oil, canola oil, vegan "mayonnaises" (such as Vegenaise), tofu, and chocolate are better choices.

All vegans should pay attention to omega-3 fatty acid intake. As an essential amino acid, omega-3 helps to conduct nerve impulses; to form the membranes around the brain, heart, muscles, and other organs; and to maintain optimum cardiovascular health. These needs can generally be satisfied by taking a teaspoon of flaxseed oil per day. Ground flaxseeds, canola oil, and walnuts are also good sources of omega-3 fats.

Carbohydrates

Carbohydrates appear to be the major fuel used during resistance exercise.3 Some researchers suggest 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.

Vitamins and minerals

When food intake increases, as it should on a weight-lifting regimen, vitamin and mineral intake naturally will increase as well. 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, vitamin D, and calcium), 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. For general recommendations for vegans, please see www.JackNorrisRd.com/links (my website) or the nutrition section in the book Simply Vegan, published by The Vegetarian Resource Group.

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 Inter-national 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.

Getting Ripped

For bodybuilders, increasing muscle mass is only half the battle. The other half is reducing body fat so that the muscles are more visible. Powerlifters might also try to lose body fat to get into a lower weight class for competition.

A vegan diet is normally lower in calories, and vegans generally have a lower Body Mass Index (a measure of weight that takes into account differences in height).9 Vegans tend to have a lower percentage of body fat than non-vegans and lacto-ovo vegetarians; however, these numbers are not always statistically significant.11,12,13,14

Bodybuilders are often encouraged to "graze," or to eat about six smaller meals a day rather than three large ones. In addition to providing a consistent source of energy for training, there is now research that shows that this may, indeed, be an effective way to reduce body fat. In a unique study, researchers at Georgia State University studied 62 elite female athletes and their energy intakes on an hourly basis.15 The athletes included rhythmic gymnasts, artistic gymnasts, middle-distance runners, and long-distance runners. Food intakes and energy expenditures for every hour of a typical training day were measured. Having more hours with at least a 300-calorie deficit (where at least 300 more calories of energy was burned than eaten for the day) was associated with higher body fat. The researchers theorized that energy deficits cause the body to slow its metabolism down such that body fat can be stored despite large energy expenditures. They noted that restricting energy intake below estimated energy needs in order to lose weight is counterproductive.

While the above study was not done on bodybuilders, the results may be directly applicable. Given that bodybuilders have been "grazing" for many years, it seems reasonable to conclude that eating numerous meals throughout the day to match energy intake with energy expenditure should help bodybuilders reach a lower body fat percentage.

During Workouts

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.

After Workouts

To my knowledge, only one study has looked at post-training meals and muscle protein synthesis. 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

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 bouts of intense exercise, therefore allowing for increased training.17 While there are still questions to be answered, we are getting more conclusive ideas about creatine all the time.

Creatine is a component of phosphocreatine (PCr) and can be synthesized in the body. It is also supplied in the diet by meat and fish. PCr provides energy during short bursts of powerful exercise, such as weight-lifting and sprinting, or during multiple bouts of high-intensity exercise, such as in soccer, rugby, and hockey.17 Depletion of PCr in muscle is associated with fatigue during such exercise.18 Supplementing with creatine has been shown to increase performance in these sports,18,19 especially in people whose creatine levels in muscle were initially on the lower side of normal.20

Vegetarians have lower levels of creatine in their blood, urine, and red blood cells.21,18 This does not necessarily mean that they have lower levels in skeletal muscle, which is where it most matters during exercise. In one study, vegetarians and meat-eaters took 7 g of creatine three times a day for six days. The vegetarians' power output over three bouts of exercise improved significantly after the six days of supplementation, while it did not change for the meat-eaters.18 In another study of vegetarians, creatine supplementation did not improve power output.22

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 of 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

The loading phase for vegetarians and non-vege- tarians 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

Safety of Creatine

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.20 No side effects have been found in people taking 20 g/day for up to five weeks.19 However, there are some anecdotal (not measured) 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 supplements.18

Summary

While there is no evidence that vegan weightlifters need to take creatine to achieve maximum results, it appears to be safe in the amounts that have been studied, and it could possibly improve performance. Supple-ment companies claim creatine is not synthesized using animal derivatives.24

Carnitine

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.21,27,28,29 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.

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

Please note that Solgar's carnitine supplement is made through yeast fermentation of beet sugar.32

Pre-Contest

Bodybuilders use a vast array of methods, some quite extreme, to lose body fat and increase muscle size in the weeks, and especially in the days, before a contest. These methods have not been studied scientifically, so I will not comment on them here. The recommendations in this article are intended to increase muscle mass and reduce body fat as much as possible, with the hope of reducing the desire to engage in extreme pre-contest strategies.

Tofu Smoothie

(Serves 1)

This smoothie is quick to make and provides protein and fat, in addition to the carbohydrates typical in a fruit smoothie. I make twice what I need and keep the other half in a container for a future meal.

Put tofu, bananas, and frozen fruit into a blender. Cover 3/4 of the ingredients with a fruit juice of your choice. Blend until smooth.

Jack Norris is the President of Vegan Outreach and author of the newsletter Making Sense of Nutrition Research. His site, www.JackNorrisRd.com/links, has links to articles about weight-training methods.

References

  1. Lemon PW, Tarnopolsky MA, MacDougall JD, Atkinson SA. Protein requirements and muscle mass/strength changes during intensive training in novice bodybuilders. J Appl Physiol. 1992 Aug;73(2):767-75.
  2. Tarnopolsky MA, MacDougall JD, Atkinson SA. Influence of protein intake and training status on nitrogen balance and lean body mass. J Appl Physiol. 1988 Jan;64(1):187-93.
  3. Lemon PW. Effects of exercise on dietary protein requirements. Int J Sport Nutr. 1998 Dec;8(4):426-47.
  4. Dietary Reference Intakes for Energy, Carbohydrates, Fiber, Fat, Protein and Amino Acids (Macronutrients). Food and Nutrition Board, Institute of Medicine. Washington, DC: National Academies Press; 2002.
  5. Davis B, Melina V. Becoming Vegan: Summertown, TN: Book Publishing Co; 2000.
  6. Messina M, Messina V. The Dietitian's Guide to Vegetarian Diets. Gaithersburg, MD: Aspen Publishers, Inc., 1996.
  7. Unpublished data from the European Prospective Investigation into Cancer (EPIC)-Oxford. Personal communication with Paul Appleby. November 1, 2002.
  8. Venkatraman JT, Leddy J, Pendergast D. Dietary fats and immune status in athletes: clinical implications. Med Sci Sports Exerc. 2000 Jul;32(7 Suppl):S389-95. Delanghe J, De Slypere JP, De Buyzere M, Robbrecht J, Wieme R, Vermeulen A. Normal reference values for creatine, creatinine, and carnitine are lower in vegetarians. Clin Chem. 1989 Aug;35(8):1802-3.
  9. Appleby PN, Davey GK, Key TJ. Hypertension and blood pressure among meat eaters, fish eaters, vegetarians and vegans in EPIC-Oxford. Public Health Nutrition 2002;5:645-654.
  10. Lambert CP, Flynn MG. Fatigue during high-intensity intermittent exercise: application to bodybuilding. Sports Med. 2002;32(8):511-22.
  11. Thomas EL, Frost G, Barnard ML, Bryant DJ, Taylor-Robinson SD, Simbrunner J, Coutts GA, Burl M, Bloom SR, Sales KD, Bell JD. An in vivo 13C magnetic resonance spectroscopic study of the relationship between diet and adipose tissue composition. Lipids. 1996 Feb;31(2):145-51.
  12. Janelle KC, Barr SI. Nutrient intakes and eating behavior scores of vegetarian and nonvegetarian women. J Am Diet Assoc. 1995 Feb;95(2):180-6.
  13. Sanders TA, Key TJ. Blood pressure, plasma renin activity and aldosterone concentrations in vegans and omnivore controls. Hum Nutr Appl Nutr. 1987 Jun;41(3):204-11.
  14. Ross JK, Pusateri DJ, Shultz TD. Dietary and hormonal evaluation of men at different risks for prostate cancer: fiber intake, excretion, and composition, with in vitro evidence for an association between steroid hormones and specific fiber components. Am J Clin Nutr. 1990 Mar;51(3):365-70.
  15. Deutz RC, Benardot D, Martin DE, Cody MM. Relationship between energy deficits and body composition in elite female gymnasts and runners. Med Sci Sports Exerc. 2000 Mar;32(3):659-68.
  16. Doi T, Matsuo T, Sugawara M, Matsumoto K, Minehira K, Hamada K, Okamura K, Suzuki M. New approach for weight reduction by a combination of diet, light resistance exercise and the timing of ingesting a protein supplement. Asia Pacific journal of clinical nutrition. 2001;10(3):226-32.
  17. Casey A, Greenhaff PL. Does dietary creatine supplementation play a role in skeletal muscle metabolism and performance? Am J Clin Nutr. 2000 Aug;72(2 Suppl):607S-17S.
  18. Shomrat A, Weinstein Y, Katz A. Effect of creatine feeding on maximal exercise performance in vegetarians. Eur J Appl Physiol. 2000 Jul;82(4):321-5.
  19. Stone MH, Sanborn K, Smith LL, O'Bryant HS, Hoke T, Utter AC, Johnson RL, Boros R, Hruby J, Pierce KC, Stone ME, Garner B. Effects of in-season (5 weeks) creatine and pyruvate supplementation on anaerobic performance and body composition in American football players. Int J Sport Nutr. 1999 Jun;9(2):146-65.
  20. Casey A, Greenhaff PL. Does dietary creatine supplementation play a role in skeletal muscle metabolism and performance? Am J Clin Nutr. 2000 Aug;72(2 Suppl):607S-17S.
  21. Delanghe J, De Slypere JP, De Buyzere M, Robbrecht J, Wieme R, Vermeulen A. Normal reference values for creatine, creatinine, and carnitine are lower in vegetarians. Clin Chem. 1989 Aug;35(8):1802-3.
  22. Clarys P, Zinzen E, Hebbelinck M, Verlinden M. Influence of oral creatine supplementation on torque production in a vegetarian and non-vegetarian population. Vegetarian Nutrition 1997 1(3):100-105.
  23. Harris R. Dietary and supplementary creatine. http://www.scitecnutrition.com/scifiles/dietary/dietary.htm Accessed on November 5, 2002.
  24. Larson E. Vegetarian diet for exercise and athletic training and performing: an update. Vegetarian Nutrition. Vegetarian Dietetic Practice Group of the American Dietetic Association. http://www.andrews.edu/NUFS/vegathletes.htm Accessed November 5, 2002.
  25. Chen W, Huang YC, Shultz TD, Mitchell ME. Urinary, plasma, and erythrocyte carnitine concentrations during transition to a lactoovovegetarian diet with vitamin B-6 depletion and repletion in young adult women. Am J Clin Nutr. 1998 Feb;67(2):221-30.
  26. Villani RG, Gannon J, Self M, Rich PA. L-Carnitine supplementation combined with aerobic training does not promote weight loss in moderately obese women. Int J Sport Nutr Exerc Metab. 2000 Jun;10(2):199-207.
  27. Lombard KA, Olson AL, Nelson SE, Rebouche CJ. Carnitine status of lactoovovegetarians and strict vegetarian adults and children. Am J Clin Nutr. 1989 Aug;50(2):301-6.
  28. Krahenbuhl S. L-Carnitine and vegetarianism. Ann Nutr Metab 2000;44:81-82.
  29. Krajcovicova-Kudlackova M, Simoncic R, Bederova A, Babinska K, Beder I. Correlation of carnitine levels to methionine and lysine intake. Physiol Res. 2000;49(3):399-402.
  30. Siebrecht S. L-Carnitine: physiological and pharmacological effects! Ann Nutr Metab 2000;44:79.
  31. Rebouche CJ, Lombard KA, Chenard CA. Renal adaptation to dietary carnitine in humans. Am J Clin Nutr. 1993 Nov;58(5):660-5.
  32. Personal communication with Solgar customer service. November 6, 2002.

Excerpts from the 2003 Issue 4:
Planned Giving
Roger Lowe explains how ordinary people can leave lasting legacies.
Nutrition Hotline
Why trans fats are bad, where they can hide, and how you can avoid them.
Note from the Coordinators
Scientific Update
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PO Box 1463, Baltimore, MD 21203
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Last Updated
July 29, 2003

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