Protein often gets hailed as the superstar nutrient when it comes to building muscle. From gym buffs to nutrition experts, the message is loud and clear: “Protein, protein, protein!” Some have even elevated it into catchy slogans that echo throughout fitness communities. But is protein truly the ultimate key to muscle growth? Or can you still make meaningful gains without hitting those often-touted high protein targets? Let’s dive into what research really says about protein intake and muscle building.
Protein Recommendations and Their Practicality
Experts frequently recommend around 1.6 grams of protein per kilogram of bodyweight daily to optimize muscle gains. For some, this number is manageable, but for others, it might be challenging—whether due to digestive capacity or financial constraints since achieving this intake often requires protein supplements. This leads to a common question: If you consume less protein than this “optimal” amount, what muscle gains can you expect?
What the Research Tells Us
Studies indicate that eating less protein generally results in smaller muscle gains compared to higher protein intake. However, the extent of this difference varies widely between studies. This variability isn’t surprising given that muscle growth depends on multiple factors besides protein—including overall diet quality, training regimen, genetics, and more.
To make sense of this complexity, systematic reviews that analyze multiple studies offer valuable insights.
Key Findings from Systematic Reviews
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2022 Review by Tagawa et al.
Analyzing 66 studies spanning approximately 20 weeks on average, this review found a dose-response relationship between protein intake and lean mass gains. For every 0.1-gram increase in protein per kilogram of bodyweight, participants gained about 0.39 kg of lean mass—up to a protein intake of 1.3 grams per kilogram, after which additional gains slowed, rising only by 0.12 kg per 0.1-gram increase. -
2018 Review by Morton et al.
Focusing on healthy young adults engaged in resistance training, this review echoed similar trends despite narrowing the subject group. The dose-response curve resembled that of the 2022 review, reinforcing that muscle gains increase with protein intake but with diminishing returns after a certain point.
Both reviews agree you can build muscle on lower protein intakes—the gains just tend to be smaller. Increasing protein gradually enhances muscle growth, but the spike in benefits tapers after crossing roughly 1.3 to 1.6 grams per kilogram.
Who Needs More Protein?
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Older Adults:
They generally require a higher protein intake to combat muscle loss (sarcopenia). However, their response to increased protein plus resistance training may not be as robust as younger individuals. -
People Cutting Calories:
Higher protein intake is particularly important during calorie restriction to preserve muscle mass while losing fat. -
Beginners:
Those new to resistance training often experience quick muscle growth, even with lower protein intake, giving them some flexibility to optimize protein over time. -
Trained Individuals:
Experienced lifters aiming to maximize growth might benefit from protein intakes as high as 2.2 grams per kilogram per day. Still, most individuals do well with around 1.6 grams.
The Bottom Line: Protein is Important, But Not Everything
The takeaway from the data and reviews is reassuring. While eating less protein than recommended may slow your muscle-building progress, it does not prevent muscle growth altogether—especially if you consistently engage in resistance training such as weight lifting.
If you find hitting high protein targets challenging, don’t let that discourage you from pursuing your muscle-building goals. Aim for consistent training first and do your best with protein intake. Over time, any improvements you make to your diet can further enhance gains.
Final Thoughts
- Building muscle requires multiple factors working in tandem: training, nutrition, recovery, and more.
- Protein supports muscle growth efficiently but excess protein beyond a certain point yields diminishing returns.
- Moderate protein intake combined with regular resistance training is sufficient for meaningful muscle gains.
- Specific groups (older adults, people cutting, experienced lifters) may benefit from higher protein intake.
- Consistency in your exercise routine matters more than chasing perfect protein numbers.
So, while the popular slogan “Don’t forget to get your protein!” holds truth, it’s okay if you’re only getting a little bit—or not hitting the “optimal” amount perfectly. Keep lifting, keep progressing, and the muscle will come.
This article is based on current research reviews and aims to give a balanced view on protein intake and muscle building—helping you tailor your nutrition to your lifestyle and goals without unnecessary stress around exact numbers.
