If you coach or train alongside anyone eating a vegan diet, you've probably heard some version of this complaint: "I did legs on Monday and I'm still wrecked on Thursday." A new study out of Brazil, published this month in the journal Nutrition Bulletin, gives that complaint some real data behind it, and the data is more interesting than a simple "meat is better" headline would suggest.
Researchers at the Federal University of Sergipe recruited fourteen physically active adults, seven who had followed a strict vegan diet for at least six months and seven omnivores, all with at least a year of consistent resistance training behind them. Everyone did the same brutal protocol: five sets to failure on the Smith machine squat and five more on the 45-degree leg press, each at 85 percent of their one-rep max. Then the researchers tracked what happened to their muscles over the next three days.
What they found split cleanly into two categories. On one hand, the vegan group reported meaningfully more soreness. On the other, their actual physical recovery, the things you can measure with a jump mat or a tape measure, looked basically the same as everyone else's.
What the researchers actually measured
This is worth walking through, because the study did something a lot of nutrition research skips: it looked at both how people said they felt and what their bodies were objectively doing, and those two things told slightly different stories.
For the subjective side, they used delayed-onset muscle soreness ratings, the familiar ache that peaks a day or two after a hard workout. For the objective side, they tracked creatine kinase and lactate dehydrogenase, two enzymes that leak into the bloodstream when muscle fibers get damaged, along with jump height, range of motion, and thigh swelling.
The soreness numbers were the clearest finding. At 24 hours post-workout, vegan participants rated their pain about 2.7 points higher on a 10-point scale than the omnivores did. At 72 hours, the gap was still about 2.6 points. For context, pain researchers generally consider a 1 to 2 point shift on this kind of scale to be the threshold where a person actually notices the difference in daily life. This wasn't a rounding error. It was a real, felt gap.
But the blood markers of muscle damage didn't differ meaningfully between the two groups, and neither did jump performance, range of motion, or muscle swelling. In other words, by the measures that most directly reflect whether your muscle tissue is actually repairing itself, the vegan lifters were doing just as well as the omnivores. They just felt worse while doing it.
The protein gap underneath it all
So what explains the soreness without the underlying damage difference? The researchers point to diet, and the numbers here are stark. The omnivores in this study were eating about 2.14 grams of protein per kilogram of body weight per day. The vegans were eating about 0.98 grams per kilogram, less than half. The gap widened further when you look at branched-chain amino acids specifically, the leucine, isoleucine, and valine that are especially important for muscle repair: the omnivores took in roughly 24 grams a day, the vegans about 9.
It's worth saying clearly that this wasn't a controlled feeding trial where researchers handed people specific meals. The team measured what these fourteen people were already eating, using repeated 24-hour dietary recalls, and then looked at how that habitual diet related to how they recovered from a standardized muscle-damage protocol. That's a meaningful distinction. It means the finding isn't "vegan diets cause soreness." It's closer to "in this small group, the vegans happened to be eating a lot less protein and fewer of the specific amino acids tied to muscle repair, and that gap tracked with how sore they got."
That distinction matters because of what other, larger studies have already shown. When researchers have deliberately matched protein intake between vegan and omnivorous lifters, at around 1.6 to 2.0 grams per kilogram in both groups, strength gains, muscle growth, and protein synthesis rates have come out essentially identical. The plant-based diet itself doesn't appear to be the limiting factor. Falling short on total protein and amino acid intake does, and it happens to be more common among people who've cut out animal foods without deliberately rebuilding their protein sources around the gap that leaves.
Why this is worth your attention if you train or coach
If you're a trainer with plant-based clients, or a gym owner whose front desk has fielded the "why am I always so sore" conversation, this study gives you a more precise way to think about it than "eat more protein" in the abstract. The useful version of the advice is specific: total protein per kilogram of bodyweight, plus attention to the amino acid profile of where that protein is coming from.
It's also worth saying what this study doesn't tell us, because the honest caveats matter here. Fourteen people is a small sample, and this was a convenience sample of young, already-trained adults in Brazil, not a randomized trial and not a group that necessarily represents plant-based lifters generally. A separate, similarly designed study in untrained women actually found the opposite pattern, with vegans reporting less soreness, which the authors attributed to the anti-inflammatory compounds common in plant-heavy diets. The truth here is probably that both things are happening at once: plant-forward diets can bring real anti-inflammatory benefits from all that fruit, vegetable, and fiber intake, while still leaving a protein and amino acid shortfall that shows up specifically in how sore someone feels after hard training. Neither story cancels the other out.
What to actually do with this, starting this week
For any client eating primarily or entirely plant-based, the target worth aiming for is somewhere in the 1.6 to 2.0 gram per kilogram range that the matched studies used, not the sub-1.0 gram range that showed up in this study's vegan group. That's a real, trackable number, not a vague suggestion to "eat more beans."
A few concrete moves make that gap closable. Building meals around higher-protein plant sources, tofu, tempeh, seitan, lentils, and protein-fortified products, gets you further than leaning on vegetables and grains alone. Combining protein sources across a day, like rice with beans or oats with a pea-protein shake, helps round out the amino acid profile, particularly the leucine and BCAA content that this study flagged as meaningfully lower in the vegan group. And because hitting these numbers by feel is genuinely hard, actually tracking intake for a week or two, rather than estimating it, is often the difference between a client who thinks they're eating enough protein and one who's eating half of what they need.
That last part is where most people, vegan or not, quietly fall short. Nobody's guessing their way to 2 grams per kilogram by accident.
Sources & References
- Mendes-Netto, R.S., de Carvalho, F.G., de Souza, A.C., da Silva Brandão, M., Oliveira, D.L., Costa, M.L., do Nascimento, M.V.S., & da Silva Grigoletto, M.E. (2026). Similar Muscle Recovery but Greater Soreness in Active Vegans on Low-Protein Diets Compared to High-Protein Omnivores Following Exercise-Induced Damage. Nutrition Bulletin, 51(3), 389-406. PubMed PMID: 42584017, DOI: 10.1111/nbu.70064. Full text via PubMed Central: PMC13522861
- Hevia-Larraín, V., et al. (2021). High-Protein Plant-Based Diet Versus a Protein-Matched Omnivorous Diet to Support Resistance Training Adaptations: A Comparison Between Habitual Vegans and Omnivores. Sports Medicine. (Cited within the above study for matched-protein comparison data.)
- Monteyne, A.J., et al. (2023). Vegan and omnivorous high protein diets support comparable daily myofibrillar protein synthesis rates and skeletal muscle hypertrophy in young adults. American Journal of Clinical Nutrition. (Cited within the above study for matched-protein comparison data.)
- Njeim, R., et al. Comparable study referenced within the primary paper, reporting more favourable DOMS-related responses in untrained vegan women, included above for balance.
- According to PubMed, all article identifiers and citation data for the primary study were retrieved directly from the National Library of Medicine's PubMed and PubMed Central databases.
This article summarizes a single, relatively small study (n=14) and should be read as an early, specific finding rather than a settled conclusion. As always, individual results vary, and anyone with significant dietary restrictions or medical conditions should work with a qualified professional before making major changes to protein intake.
Hit Your Number, Don't Guess It
The gap this study points to, roughly 1 gram of protein per kilogram between what the vegan lifters were eating and what the matched-protein research suggests they need, is exactly the kind of thing that's nearly impossible to catch by feel. It's easy to think you're eating enough protein. It's much harder to actually know, meal by meal, without tracking it.
That's what Totality Nutrition is built for. It's a straightforward macro-tracking app with an Australian-first food database, so the plant-based staples, protein powders, and packaged foods you or your clients actually buy are already in there, along with barcode scanning to make logging fast rather than a chore. Set a custom protein target based on your actual bodyweight, whether that's 1.6, 1.8, or 2.0 grams per kilogram, and see in real time whether you're closing the gap or still falling short.
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