Researchers are testing whether older adults can maintain strong leg muscles while eating a vegan diet. Since plant-based foods have less protein than meat and dairy, scientists want to know if veganism affects muscle health in people over 65. This 12-week study will compare three groups: people eating their normal diet, people eating vegan, and people eating vegan while doing strength exercises twice a week. By measuring leg muscle size with special imaging, researchers hope to understand whether veganism is safe for older adults’ muscles and whether adding exercise can help protect muscle strength.

The Quick Take

  • What they studied: Whether eating a plant-based (vegan) diet affects leg muscle size in older adults, and whether adding strength training twice a week helps protect muscles
  • Who participated: 72 people aged 65 and older living in their own homes, with healthy weight ranges, who will be randomly assigned to three different eating and exercise groups
  • Key finding: This is a research plan, not yet completed results. The study will measure leg muscle volume using MRI scans after 12 weeks to see which diet and exercise combination works best for maintaining muscle in older adults
  • What it means for you: If you’re over 65 and considering a vegan diet, this research may help answer whether you need to do strength training to keep your muscles healthy. Results should be available in 2025, but talk to your doctor before making major diet changes

The Research Details

This is a randomized controlled trial, which is considered one of the strongest types of research. Seventy-two older adults will be randomly divided into three equal groups. One group will continue eating their normal diet with meat and dairy. The second group will switch to a vegan diet with no animal products. The third group will eat vegan while also doing strength exercises twice per week. All groups will attend monthly nutrition education meetings to help them follow their assigned diet correctly.

The study lasts 12 weeks, with measurements taken at the start, after 6 weeks, and at the end. Researchers will use MRI machines (the same technology used in hospitals) to measure the actual size of thigh muscles. They’ll also track what people eat using food diaries and measure physical activity with special devices worn on the body.

Beyond just muscle size, scientists will also check blood work, bone health, gut bacteria, and how people feel digestively. This gives a complete picture of how veganism affects overall health in older adults.

This research design is important because it randomly assigns people to groups, which helps prove that diet—not other factors—causes any differences. Using MRI to measure actual muscle size is more accurate than just weighing people. By testing vegan diet alone and vegan diet plus exercise, researchers can figure out whether exercise is necessary to protect muscles on a plant-based diet. This matters because more older adults are choosing vegan diets for health and environmental reasons, but we don’t have enough research on whether it’s safe for maintaining muscle strength as we age.

This study has several strengths: it’s randomized (reducing bias), uses precise MRI imaging instead of estimates, includes detailed dietary tracking, and measures multiple health markers beyond just muscle. The study is registered publicly before starting, which increases transparency. However, this is a research protocol (the plan), not yet completed results. The relatively small sample size (72 people) means results may not apply to all older adults. The 12-week timeframe is short—longer studies might show different results. Participants must be relatively healthy with normal weight ranges, so findings may not apply to very overweight or underweight older adults.

What the Results Show

This document describes the research plan rather than actual results. The study is designed to measure thigh muscle volume using MRI scans at the beginning and end of 12 weeks. Researchers will compare muscle size changes between the three groups: regular diet, vegan diet, and vegan diet with strength training. The primary question is whether eating vegan causes muscle loss compared to eating meat and dairy, and whether adding strength exercises twice weekly prevents that loss.

The study will also measure how quickly muscles build new protein during the first 10 days using a special water-based test. This helps explain the biological mechanisms behind any muscle changes observed. Secondary measurements include overall body composition, how much fat is mixed into muscle tissue, muscle strength tests, bone density, blood sugar control, vitamin levels (especially B12 and iron), inflammation markers, and gut bacteria composition.

Results will be analyzed using statistical tests that compare the three groups and track changes over time. The researchers will publish findings once the 12-week study is complete, likely in 2025.

Beyond muscle size, this study will examine many other health markers important for older adults. Bone health is crucial since vegans sometimes have lower bone density, so researchers will measure bone mineral density and markers of bone turnover. Blood work will check vitamin B12, iron, and vitamin D levels—nutrients that can be lower in plant-based diets. Metabolic health will be assessed through blood sugar and insulin levels. Inflammation markers will show whether veganism affects the body’s inflammatory response. Gut bacteria composition will be analyzed because plant-based diets significantly change the microbiome, which may affect overall health. Researchers will also track digestive symptoms since some people experience bloating or changes when switching to vegan eating.

Previous research suggests that plant-based proteins are lower quality than animal proteins for building muscle, which is why this study is needed. Most existing studies on veganism focus on younger adults or don’t specifically measure muscle in older people. Some research shows older adults need more protein to maintain muscle, and plant-based diets typically provide less protein overall. However, few studies have tested whether strength training can compensate for lower protein intake on a vegan diet in this age group. This research fills that gap by directly comparing vegan and non-vegan diets in older adults and testing whether exercise helps protect muscles.

This study has several important limitations. First, it’s relatively short (12 weeks), so we won’t know about long-term effects of veganism on muscle. Second, the sample size is small (72 people), which means results may not apply to all older adults. Third, participants must have healthy weight ranges (BMI 23-32), so findings may differ for very overweight or underweight people. Fourth, the study is in one country with one population, so cultural and genetic differences might affect results elsewhere. Fifth, people in the study know they’re being studied and receive nutrition education, which might change their behavior differently than people making diet changes on their own. Finally, this is a research protocol—actual results aren’t available yet, so we can’t know if the study will work as planned or if unexpected findings will emerge.

The Bottom Line

Wait for study results (expected 2025) before making major diet changes based on this research. If you’re over 65 and considering veganism, consult your doctor first. If you do choose a vegan diet, this research suggests that adding strength training twice weekly may help protect your muscles. Ensure adequate protein intake from plant sources and consider B12, iron, and vitamin D supplementation, which are commonly low in vegan diets. These recommendations have moderate confidence since the study isn’t yet complete.

This research is most relevant for people over 65 considering or already following a vegan diet, especially those concerned about maintaining muscle strength and independence. It matters for healthcare providers advising older patients about dietary changes. It’s less relevant for younger adults, whose muscle maintenance is easier, or for people with medical conditions requiring specific diets. People already doing regular strength training may see different results than sedentary individuals.

The study itself runs 12 weeks, but you shouldn’t expect to see major muscle changes in that timeframe. Muscle building typically takes 8-12 weeks to become measurable, so realistic expectations are modest changes over 3 months. Long-term benefits or problems might take months to years to appear. Results from this study should be published in 2025, giving us better guidance for older adults considering veganism.

Want to Apply This Research?

  • Track weekly protein intake (grams per day) from plant sources and compare it to recommended amounts for your age. Also log strength training sessions (frequency and duration) to correlate with any changes in energy or muscle perception
  • If following a vegan diet, use the app to set a reminder for twice-weekly strength training sessions and track plant-based protein sources at each meal to ensure adequate intake. Create a checklist for supplementing B12, iron, and vitamin D if vegan
  • Measure thigh circumference monthly as a simple proxy for muscle changes (though less accurate than MRI). Track strength improvements through exercises like leg presses or squats. Monitor energy levels, muscle soreness, and digestive symptoms weekly. Review blood work annually to check B12, iron, and vitamin D levels if vegan

This article describes a research study protocol, not completed results. The findings discussed are preliminary and based on the study design, not actual data. This information is educational only and should not replace medical advice from your healthcare provider. Before making significant dietary changes, especially if you’re over 65 or have existing health conditions, consult your doctor or registered dietitian. Individual results vary based on genetics, overall health, and lifestyle factors. This research is ongoing and results may differ from the protocol described.