Researchers pooled eleven controlled trials on this question. The rice was along for the ride.
Not one of the eleven trials found that extra carbs built significantly more muscle.
You've been measuring rice on a kitchen scale for months.
Not because you love rice. Because every training partner, every bodybuilding forum, every macros calculator told you the same thing: carbs build muscle. The chicken is for protein. The broccoli is for micronutrients. And the rice is for gains.
In 2024, three academics wrote a piece in The Conversation arguing that carbs are "as important as protein" for muscle growth. They opened with a Mr. Universe winner's anecdote. That article still ranks on page one.
Then a team of researchers did something nobody else on that search results page had done. They pooled every controlled trial their search could find that met their criteria on this exact question.
None of eleven controlled trials found that carbs independently drive muscle growth. Protein was matched in all of them. The carbs looked like a way to eat enough calories.
- Researchers pooled eleven controlled trials and found no significant effect of carb intake on muscle growth — and none of the eleven found one on its own.
- Most studies tracked "lean mass" using scans that can't tell the difference between real muscle and stored glycogen plus water — the two that measured muscle size directly leaned the other way, without significance.
- Low-carb groups tended to lose more fat (not significantly); the authors' hypothesis is that cutting carbs made people eat less without meaning to.
- The researchers rated their own confidence at two out of four — a small positive effect of carbs hasn't been ruled out, but no lab has detected one yet.
- Carbs help you eat enough calories to support growth, but the evidence does not show them sending a growth signal to your muscles. The carb slider moves freely as long as total food and protein stay sufficient.
What Eleven Labs Found
In February 2026, a team led by Menno Henselmans published the first meta-analysis directly testing whether carbohydrate intake affects muscle growth during resistance training. The study appeared in Sports Medicine and pooled eleven randomized controlled trials — every study their search found that met its criteria, spanning over a decade of research.
The trials averaged 20.6 participants each, about 227 in all — predominantly trained males between 18 and 65, the review's age limits — split into higher-carb and lower-carb groups while keeping protein matched.
The result: no significant difference in muscle growth. The pooled effect leaned slightly toward more carbs, but it was small and not statistically significant.
But the number alone isn't what makes this hit. No single study found a significant effect either way. The differences between labs were no larger than chance would produce (I² = 0).
When the researchers removed one study at a time to test whether any single trial was driving the result, the answer held. When they restricted the analysis to the three studies that matched calories between groups, the estimate was the same (0.15) and still not significant.
In these trials, extra carbs added no significant muscle. Protein was matched between the groups in every trial; carbohydrate intake was what the trials varied.
Why Everyone Thought They Knew Better
If carbs don't build muscle, why has every coach, every supplement company, and every search result been saying otherwise?
Part of the answer lives in what "muscle growth" actually means when researchers measure it. Nine of the eleven studies tracked "lean mass" or "fat-free mass" using whole-body scans. The problem: those scans can't tell the difference between real muscle tissue and glycogen stored inside that tissue, plus the water that tags along.
One study illustrated the issue viscerally. After ten weeks on a ketogenic diet, participants reintroduced carbs for a single week. Their "fat-free mass" jumped 4.8% in one week.
The authors put that jump down, most likely, to glycogen refilling the muscle, with the water stored alongside it; the control group, which kept its carbs, showed no change that week. The scan recorded it as "lean mass gained."
The two studies that used a different approach — measuring actual muscle thickness with ultrasound, imaging the actual muscle directly — told a different story. When the researchers isolated those two, the direction of the result reversed. The lower-carb groups came out slightly ahead, though not significantly.
Two studies is too few to draw a firm conclusion, and the researchers were transparent about that. But the direction flip hints at something the whole-body scans may hide. The "advantage" of carbs for muscle growth may have been glycogen and water masquerading as real muscle on a scan.
A typical strength-training session depletes your muscle glycogen by less than half. The threshold where low glycogen actually starts hurting performance is well below what a normal workout touches — for a typical session your muscles likely had enough fuel, whether you ate rice beforehand or not.
What the Scientists Themselves Don't Know Yet
Here is where most coverage of this study would stop. The finding is dramatic enough to carry a headline and move on.
But the researchers rated their own confidence at two out of four — meaning future research could still shift the conclusion.
The reasons are honest. Only eleven trials met the criteria. The average trial enrolled about 20 participants and lasted about eight and a half weeks.
Future research could still land anywhere from carbs hurting a little to helping moderately. A world where carbs help a little hasn't been ruled out.
What has been established: across these eleven trials, the effect of carbs on muscle growth was either zero or too small for any of them to detect. That consistency — not the size of any single study — is the strongest signal in the data.
What Carbs Actually Do
If carbs aren't building muscle, what are they doing on your plate?
The meta-analysis offers a clue in its secondary data. When the researchers analyzed fat mass changes separately, they found a trend toward greater fat loss in the lower-carb groups. The effect was not significant (p = 0.09), but it pointed one way: people eating fewer carbs tended to end up leaner.
That pattern lines up with a well-documented phenomenon. Low-carb diets suppress appetite. People on them tend to eat fewer total calories without trying. Several trials in the meta-analysis fit this pattern: participants reported similar intakes, but their body composition changes told a different story.
The lead author's own summary strips the finding to a single principle: this is about energy intake, not carbohydrate intake. On this evidence, carbs don't send a separate growth signal to your muscles. They make it easy to eat enough food.
Cut carbs too hard on a bulk, and your muscles won't starve for carbs. They'll starve for calories — and that distinction is the practical point.
In these trials, carbs did not show up as a muscle-building tool. They look more like a calorie vehicle: the bigger risk of going low-carb is eating too little.
What This Changes
The lead author, Menno Henselmans, isn't working from a disconnected academic office. He's the founder of Bayesian Bodybuilding — one of the most recognized evidence-based fitness coaching brands online — and coaches physique athletes full-time in six languages.
The person behind "Henselmans et al. 2026" in Sports Medicine is the same person answering DMs from lifters about their macros.
His team's analysis of eleven controlled trials pointed one way. The evidence does not support carbs as an independent driver of muscle growth, provided total calories and protein are sufficient.
That finding doesn't stand alone. A separate systematic review by the same research group examined 49 studies on carbs and strength training performance. The vast majority — including all 16 studies that matched calories — showed no benefit of higher carb intake. [1]
The evidence converges from both angles: extra carbs showed no significant extra muscle, and they don't generally improve the training quality that triggers growth either.
If you enjoy rice and it helps you hit your calorie target on a bulk — keep eating it. The calories are doing real work even if the carbs specifically aren't building muscle. If you want to cut carbs for a leaner recomp or simply prefer eating that way — the pooled data found no significant cost to muscle growth, and the authors' caveat is to keep total food and protein where they need to be.
The anxiety about losing muscle by cutting carbs was built on something eleven labs couldn't find evidence for. The authors' practical advice is simpler: eat enough food, eat enough protein, and the carb slider moves freely.
Which raises the next question you can't avoid. If carbs don't affect how much muscle you build, do they affect how hard you can push in the gym? Can you still hit the same squat on half the carbs? Six controlled trials already tested that.
The finding doesn't land the same way for everyone.
If the goal right now is gaining size, the bigger risk of dropping carbs, on this evidence, isn't muscle loss — it's accidentally eating less food. Carbs are the easiest macro to eat in volume, and removing them without replacing the calories elsewhere is how a bulk stalls.
If the goal is getting leaner while keeping muscle, this study says the carb number is a free variable. Total food and protein are the constraints. The carbs adjust to preference, not to a formula.
What other research found
What this means for you
Several trials in this meta-analysis directly compared ketogenic diets against normal carb intakes during resistance training. None found a significant difference in muscle growth — keto showed no significant cost to gains.
The companion review from the same research group found the same pattern for strength: 39 of 49 studies showed no performance benefit from extra carbs, and all 16 that matched calories found no difference at all.
The one thing to watch is total food intake. Keto tends to blunt appetite, which is useful for fat loss but can quietly undercut a bulk.
This is where the calorie-vehicle finding bites hardest. One study in the meta-analysis, in which the same lifters ate both ways, found that the higher-carb phase ended in a substantially larger energy surplus despite similar reported intakes: about 5,300 kcal more over the study, by the authors' estimate.
In the higher-carb phase they gained fat and lean mass; in the lower-carb phase they lost both, suggesting they were eating less without realizing it.
Across the pooled trials, dropping carbs showed no significant cost to muscle. It's risky for your calorie target.
Nine of the eleven studies in this meta-analysis used whole-body scans that can't separate real muscle from stored glycogen and water. One study showed a 4.8% jump in "lean mass" in a single week after reintroducing carbs, which the authors put down most likely to glycogen refilling.
If a scan showed impressive lean mass gains during a high-carb phase, some of that number may have been glycogen flooding back into tissue, not real muscle. The two studies that measured actual muscle thickness found a slightly different story.
Before you change anything
Predominantly trained males between 18 and 65 doing resistance training. That's who was tested across the eleven trials.
Only one study included women exclusively, and two included untrained beginners. Women and older adults are significantly underrepresented in this evidence base — the researchers flagged this themselves as a gap that future studies need to fill.
If you're a trained man doing conventional gym work, the data most directly represents you. If not, the findings don't contradict — they just haven't been tested as thoroughly in your group.
The trials averaged about eight and a half weeks. That covers a single training block, not a training career. The authors call for trials longer than 12 weeks to see whether short-term results hold.
The studies also varied widely in how much they changed carb intake — from small supplemental differences to full ketogenic diets. Whether a specific carb dose matters differently than a broad high-vs-low comparison is a question this evidence base can't answer yet.
The researchers rated their own confidence in this finding as low — two out of four on a standard scale. That means future research could shift the conclusion.
The evidence can't rule out a small positive effect of carbs on muscle growth. What it can rule out is a moderate or large one. None of the eleven trials found a significant difference.
That consistency — eleven independent teams finding the same thing — is what carries the signal, even with a small total sample of about 227 participants.
On the muscle question, the trials found no significant extra muscle from extra carbs. But once you've freed your carb intake from muscle-growth anxiety, a new question hits the moment you walk into the gym: will the bar feel heavier?
Six controlled trials already measured whether carb intake changes how much weight you can move. The answer runs parallel to this one, but the details have their own surprises.
What This Study Found
All findings from this paper, in plain language.
- Across eleven controlled trials, eating more carbs made no significant difference to how much muscle people built during strength training.
- The result held no matter which individual study was removed — no single trial was driving the finding.
- Even when total calories were matched between groups, the carb level still made no significant difference to muscle growth, in the three studies that qualified.
- The two studies that measured actual muscle thickness with imaging leaned slightly, and not significantly, toward the lower-carb groups — the opposite direction to the whole-body scans.
- The researchers rated the overall certainty of evidence as low — two out of four — meaning future studies could change the conclusion.
- Whole-body composition scans may have confused glycogen and water stored in muscle with actual muscle tissue, inflating the apparent results in higher-carb groups.
- Lower-carb groups tended to lose more fat, possibly because they were accidentally eating fewer total calories — not because carbs are inherently fattening.
- A typical strength-training session depletes less than half of your muscle's stored energy, well below the level where performance starts to suffer.
- Carbs appear to function as a calorie delivery system rather than a muscle-building signal — they can help you eat enough food, and the evidence does not support them as an independent trigger for growth.
- The data rules out a large benefit of carbs for muscle growth, but can't completely rule out a small one — future studies could still report anything from a small negative to a moderate positive effect.