by Reed Mangels, PhD, RD
There is good evidence that a combination of resistance exercise and a relatively high protein intake increases muscle mass and strength. Can a vegan diet promote increased muscle mass and strength during resistance training? That’s what a recent study (1) asked.
What is the study?
The study subjects were young women who had not engaged in a regular exercise program for at least 6 months before the start of the study. They were either vegans who had followed a vegan for an average of three years before the study started or non-vegetarians who either ate meat daily or at least three times a week. The study included 25 vegan women and 20 non-vegetarian women. The women ate their usual food throughout the study and did not take protein, amino acid, or creatine supplements. They reported what they ate throughout the study.
The women participated in a 16-week total-body resistance training program directly supervised by experienced trainers. Twice a week, on non-consecutive days, they did strength training targeting specific major muscle groups including exercises such as leg curls, bench presses, abdominal crunches, and pull-downs. Total training volume-load (sets x load x repetitions) did not differ between groups. In other words, the two groups trained similarly.
At the beginning and the end of the study, the women’s thigh and calf muscle thickness were measured with ultrasound and their strength was measured.
What did this study find?
At the end of the study period, both groups had a significant increase in muscle thickness in their thigh and in overall strength. There was no significant difference between the groups. Diet records showed that the vegans consumed an average of 1.0 grams of protein per kilogram body weight and the nonvegetarians consumed an average of 1.3 grams of protein per kilogram body weight. The somewhat higher protein intake in the nonvegetarians did not result in greater muscle or strength gain.
The researchers commented that the women’s protein intakes which were modestly above the RDA of 0.8 grams of protein per kilogram body weight “likely falls within an effective range to support muscle adaptations, particularly in previously untrained young women” (1). They concluded, “both vegetarian [vegan] and nonvegetarian diets can effectively support early gains in muscle mass and strength when nutritional and training conditions are comparable” (1).
Reference:
- Martini GL, Schemes MB, Strey B, et al. No differences in muscular adaptations to long-term resistance training between young strict vegetarian and non-vegetarian women. Scand J Med Sci Sports. 2026;36(2):e70224.
To read more about vegan diets for athletes see: Athletes & Vegan/Vegetarian Diets
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