AumaïProtein Source & Timing: Do They Build Muscle? 2026
A University of Illinois trial found protein source and meal timing didn't change muscle growth when daily protein was matched. Here's what to actually track.
You just finished a hard set of squats and you're standing in the kitchen with two options: a chicken breast or a bowl of lentils and rice. Then a second question hits. Should you spread protein evenly across the day, or is it fine to eat most of it at dinner? A randomized controlled trial from the University of Illinois Urbana-Champaign suggests both choices matter less than the number most people ignore: your total protein for the day.
What the study actually tested
Researchers led by Nicholas Burd ran a nine-day controlled-feeding trial with 40 physically active adults (28 men, 12 women, average age 25). Everyone trained with weights three times during the study. The team split participants into four groups: omnivorous or vegan diets, each with protein either balanced across five meals or loaded unevenly toward the end of the day. Daily protein was held at 1.1 to 1.2 grams per kilogram of body weight for all groups.
Key Takeaway: When total daily protein was matched at roughly 1.1 to 1.2 g/kg, muscle protein synthesis did not differ between vegan and omnivorous eaters, or between even and uneven meal timing.
To measure muscle building, the researchers used deuterated water (heavy water) as a tracer, which lets them track myofibrillar protein synthesis across whole days rather than from a single post-workout snapshot. That design matters, because older studies that favored animal protein mostly measured the response to one meal.
Source: plant or animal came out even
The muscle-building rates were statistically similar across all four groups: 3.04% per day for omnivore-unbalanced, 2.43% for omnivore-balanced, 2.52% for vegan-unbalanced, and 2.49% for vegan-balanced. In plain terms, a varied whole-food vegan diet supported muscle synthesis about as well as a meat-based one over the nine days.
Stat: Daily myofibrillar protein synthesis ranged from 2.43% to 3.04% across all four groups, with no significant differences between them.
This challenges the older belief that animal protein is clearly superior, which came from single-meal biopsy studies. Burd's point is that a day of mixed plant foods delivers a broad amino acid profile, even if one individual food is lower in a given amino acid. If you're curious how this fits the broader debate, our look at whether more protein is actually better covers the longevity side.
Timing: even spacing was not required
Many coaches recommend 20 to 40 grams of protein every few hours to maximize each muscle-building window. In this trial, the group that ate only 10% of protein at breakfast, 30% at lunch, and 60% at dinner built muscle at the same rate as the group that spread 20% across five meals.
Key Takeaway: Hitting your daily protein target appears to matter more than splitting it into perfectly even doses.
A caution worth keeping: participants were young, healthy adults. Older adults often show anabolic resistance and may still benefit from a solid protein dose per meal. This study does not overturn that nuance.
What this means for your plate
The practical headline is simple. Pick protein sources you enjoy and will eat consistently, then aim for a daily total that supports your goals. For active people building muscle, intakes around 1.2 to 1.6 g/kg per day are commonly cited, and this trial used the lower end and still saw gains. Our guide to how much protein you actually need breaks the numbers down by goal and body weight.
Tracking total protein across a day is where most people slip, especially when meals come from mixed sources like beans, tofu, yogurt, and fish. Logging each meal by text, photo, or voice makes the daily total visible, which is the number this study suggests you should actually watch. If blood sugar is also on your radar, the pea protein preload trick is a related read.
The bottom line
One trial does not close a debate, and muscle mass over months (not just synthesis over nine days) is the outcome that ultimately counts. Still, the evidence here is a relief for anyone who worried they were eating protein wrong. Source and timing give you flexibility. Your daily total is the lever worth pulling.
Sources
- Impact of Vegan Diets on Resistance Exercise-Mediated Myofibrillar Protein Synthesis in Healthy Young Males and Females: A Randomized Controlled Trial, Askow, Burd et al., Medicine & Science in Sports and Exercise, 2025
- Omnivorous? Vegan? Makes no difference to muscle building after weight training, study finds, University of Illinois News Bureau, 2025
FAQ
Does vegan protein build as much muscle as animal protein? In this nine-day trial, a varied whole-food vegan diet supported muscle protein synthesis at rates similar to an omnivorous diet when total protein was matched at 1.1 to 1.2 g/kg per day. A full day of mixed plant foods can supply a broad amino acid profile.
Do I need to eat protein every few hours to build muscle? Not necessarily. Participants who ate 60% of their protein at dinner built muscle at the same rate as those who spread it evenly across five meals. Hitting your daily protein target appears to matter more than perfectly even spacing, at least in young, healthy adults.
How much protein should I aim for per day? This study used 1.1 to 1.2 grams per kilogram of body weight and still saw muscle gains during training. Many guidelines suggest 1.2 to 1.6 g/kg for active people building muscle. Individual needs vary with age, goals, and activity level.
Does this apply to older adults? Possibly not fully. The participants were around 25 years old. Older adults often experience anabolic resistance and may benefit from a sufficient protein dose at each meal, so per-meal amounts can still matter with age.
-- Selena