Researchers compared 71 women—35 who eat only plants and 36 who eat meat—to see if their different diets affected their muscle strength and bone health. Even though the vegetarian women ate less protein, they ate more carbohydrates to make up for it, keeping their total calories similar. The study found no major differences in muscle strength, muscle size, or bone density between the two groups. However, vegetarian women weren’t getting enough calcium, which is important for bones. This suggests that vegetarians can build and maintain muscle just as well as meat eaters, but they need to pay attention to getting enough calcium.

The Quick Take

  • What they studied: Whether women who eat only plants have different muscle strength, muscle size, and bone health compared to women who eat meat
  • Who participated: 71 healthy women in their late twenties—35 strict vegetarians (eating no meat, poultry, or fish) who had followed this diet for about 3 years, and 36 women who eat meat. None of the women did regular strength training.
  • Key finding: Vegetarian and non-vegetarian women had similar muscle strength, muscle size, and bone density, even though vegetarians ate about 30% less protein. Both groups ate roughly the same total calories because vegetarians ate more carbohydrates.
  • What it means for you: If you’re vegetarian or thinking about becoming vegetarian, you can likely build and maintain muscle just as well as someone who eats meat—as long as you eat enough total calories and get adequate protein from plant sources. However, you should make sure you’re getting enough calcium, which vegetarians often miss.

The Research Details

This was a cross-sectional study, which means researchers took a snapshot in time of two different groups of women and compared them. The 71 women (35 vegetarian, 36 non-vegetarian) came to a lab where researchers measured their body composition using a special X-ray machine called a DEXA scan, which shows how much muscle, fat, and bone you have. The women also did muscle strength tests where they pushed against a machine to measure their leg strength, and they performed a vertical jump test to measure explosive power.

To understand what they were eating, all participants kept detailed food records for three days, writing down everything they consumed. This gave researchers a clear picture of how much protein, carbohydrates, fat, and other nutrients each group was getting. The vegetarian group had been following their diet for an average of about 3 years, so they were experienced with their eating pattern.

This research approach is important because it lets researchers compare real people living their normal lives, rather than forcing people to follow a specific diet in a lab. By looking at women who had already chosen to be vegetarian, the study shows what actually happens when people follow these diets long-term. The muscle strength tests and bone scans provide objective measurements rather than relying on what people remember or report.

This study has some strengths: it used precise scientific equipment to measure muscle and bone, and it included detailed food records rather than just asking people to remember what they ate. However, the study is relatively small (71 women) and only looked at women in their late twenties who don’t do strength training, so the results may not apply to older women, men, or people who already exercise regularly. The study was done at one point in time, so we can’t tell if differences developed over time. The researchers couldn’t control for all factors that might affect muscle and bone, like how much people exercised or their family history.

What the Results Show

The most important finding was that vegetarian and non-vegetarian women had nearly identical muscle strength and muscle size. When researchers measured how much force the women could produce by extending and flexing their knees, there were no meaningful differences between groups. Similarly, when women performed a vertical jump test (a measure of explosive leg power), both groups performed equally well.

Bone health was also similar between groups. Using the DEXA scan, researchers measured bone mineral density (how tightly packed the bone is) and bone mineral content (total amount of minerals in bones). Neither of these measurements differed significantly between vegetarian and non-vegetarian women, suggesting that vegetarian diets don’t harm bone strength in young women.

The dietary analysis revealed why these similarities existed despite protein differences. Vegetarian women ate about 30% less protein than non-vegetarian women (1.0 grams per kilogram of body weight versus 1.3 grams). However, both groups ate roughly the same total calories. Vegetarian women compensated for lower protein by eating more carbohydrates. Importantly, even though vegetarians ate less protein, they still met the minimum recommended daily protein intake, which appears to be sufficient for maintaining muscle in untrained women.

One important secondary finding was that vegetarian women were not getting enough calcium. The recommended daily intake is 1,000-1,200 mg, but vegetarian women averaged only about 800 mg per day. Non-vegetarian women also fell slightly short but were closer to recommendations. This calcium shortfall is concerning because calcium is essential for bone health, and inadequate intake over many years could potentially lead to weaker bones later in life. The study also found that vegetarian women’s carbohydrate intake was significantly higher (about 55% of calories versus 47% for non-vegetarians), which helped them maintain similar total energy intake despite eating less protein.

This study aligns with previous research suggesting that well-planned vegetarian diets can support normal muscle development and bone health in young adults. However, it adds new information by directly comparing untrained women and measuring both muscle function and bone health in the same study. The finding about calcium inadequacy in vegetarians confirms what other nutrition research has shown—that vegetarians need to be intentional about calcium sources like fortified plant milks, leafy greens, and supplements. The protein findings support the idea that the minimum recommended protein intake (0.8 grams per kilogram of body weight) may be adequate for sedentary people, though people who exercise regularly typically need more.

This study has several important limitations. First, it only included 71 women in their late twenties who didn’t do strength training, so results may not apply to men, older adults, or people who exercise regularly. Second, the study captured only one moment in time, so we can’t tell if differences develop over years of following these diets. Third, the researchers couldn’t control for all factors that might affect results, such as family genetics, stress levels, sleep quality, or how much people exercised outside the lab. Fourth, the vegetarian group had only been following their diet for about 3 years on average, so we don’t know what happens with longer-term adherence. Finally, the study was relatively small, so some real differences might have been missed just by chance.

The Bottom Line

Based on this research, vegetarian women can maintain muscle strength and bone health similar to non-vegetarian women, provided they: (1) eat enough total calories to meet their energy needs, (2) consume adequate protein from plant sources (aiming for at least the minimum recommendation of 0.8 grams per kilogram of body weight, though 1.0-1.2 grams may be better), and (3) ensure adequate calcium intake through fortified plant milks, leafy greens, tofu, or supplements (aiming for 1,000-1,200 mg daily). These recommendations have moderate confidence because the study was small and only included young, untrained women. If you do strength training or are older, you may need more protein than the minimum recommendation.

This research is most relevant to young women (roughly 20s-30s) who are vegetarian or considering becoming vegetarian and want to know if they can maintain muscle and bone health. It’s also useful for healthcare providers and nutritionists counseling vegetarian clients. However, the findings may not apply to men, older adults, people with existing bone or muscle problems, or people who do regular strength training (who have different nutritional needs). If you’re pregnant, breastfeeding, or have any medical conditions, consult with a healthcare provider before making major dietary changes.

Since this study only looked at one point in time, we can’t say exactly how long it takes to see effects. However, based on general nutrition science, if you’re switching to a vegetarian diet, you should expect your body to adapt over several weeks to months. Bone changes happen more slowly—typically taking months to years to become noticeable. If you’re concerned about maintaining muscle while vegetarian, focus on consistent adequate protein and calorie intake from day one, and consider doing strength training, which wasn’t studied here but is known to help maintain muscle.

Want to Apply This Research?

  • Track daily protein intake (in grams) and calcium intake (in milligrams) for vegetarian users. Set a goal of at least 0.8 grams of protein per kilogram of body weight and 1,000-1,200 mg of calcium daily. Log these nutrients weekly to identify patterns and gaps.
  • For vegetarian users, implement a ‘calcium check’ feature that prompts them to log one calcium-rich food or supplement daily. Create a simple list of plant-based calcium sources (fortified plant milks, tofu, leafy greens, tahini) with portion sizes and calcium content to make meeting calcium goals easier.
  • Establish a monthly review where vegetarian users can see their average protein and calcium intake. If calcium is consistently below 1,000 mg, suggest adding one fortified food or supplement. For users doing strength training, recommend increasing protein tracking to ensure they’re meeting higher needs (1.2-1.6 grams per kilogram of body weight).

This research describes findings from a small study of young, untrained women and should not be considered medical advice. Individual nutritional needs vary based on age, activity level, health status, and other factors. Before making significant dietary changes, especially if you have existing health conditions, are pregnant or breastfeeding, or take medications, consult with a healthcare provider or registered dietitian. This study does not replace personalized medical or nutritional guidance. If you experience symptoms of nutritional deficiency or bone problems, seek professional medical evaluation.