HYPE: More protein means more muscle — “proteinmaxxing”
But what does the evidence actually show?
Increasing protein can improve muscle gains when it addresses a shortfall and accompanies resistance training. The extra benefit is usually modest, and more is not indefinitely better. Around 1.6 g of total daily protein per kilogram of body weight is a useful research reference for many healthy adults training for muscle, not a universal threshold or a personalised prescription.
Why people believe this
Proteinmaxxing means prioritising protein in practically everything: shakes, bars, snacks and increasingly large daily targets. The strongest version of the argument is sensible. Muscle needs amino acids, exercise stimulates adaptation, and inadequate protein can restrict recovery and growth.
Protein ingestion stimulates muscle protein synthesis: the process of making new muscle proteins. Resistance exercise helps direct that response towards adaptation. Leucine, an essential amino acid, participates in signalling this process. It is easy to turn that mechanism into “if some helps, much more must help more”. But does a larger short-term signal reliably mean bigger muscles months later?
What the evidence actually shows
Protein helps, but training does most of the work
Morton and colleagues combined 49 studies involving 1,863 participants. Protein supplementation produced additional gains in fat-free mass and strength during resistance training. The average additional fat-free-mass gain was about 0.3 kg across the study periods. Fat-free mass includes more than muscle, and this is an average benefit, not a guaranteed result.
Read the research ↗Their dose-response analysis estimated a plateau near 1.62 g/kg/day of total protein, with a wide uncertainty interval of roughly 1.03–2.20 g/kg/day. That analysis is a statistical estimate across study groups. It does not prove that every person stops responding at exactly 1.6, or that 2.2 is necessary for everyone.
Food and supplements contribute to the same total
Nunes and colleagues found small additional improvements in lean body mass and lower-body strength when higher protein intake accompanied resistance exercise. The interventions included foods as well as supplements. Evidence without resistance exercise was much thinner. A high-protein product does not replace a training stimulus.
Read the research ↗Starting intake changes the question
Biersteker and colleagues studied 295 older adults over 12 weeks of supervised resistance training. A protein intervention did not significantly improve overall strength, lean mass or physical performance beyond training alone. Exploratory analyses suggested greater strength gains among those starting with lower protein intake. Those subgroup findings need confirmation; they support checking adequacy rather than assuming everyone benefits from more.
Read the research ↗Can you absorb more than 30 g at a meal?
A larger meal can produce a longer response
Trommelen and colleagues compared 25 g and 100 g of protein after exercise. The larger amount produced a greater and longer anabolic response over the measured recovery period. This challenges a rigid claim that all protein above 30 g is simply wasted. It did not test whether eating 100 g at each meal produces greater long-term muscle or strength gains.
Read the research ↗Absorption, muscle-protein synthesis and lasting muscle growth are different outcomes. Amino acids also support other tissues and can be used for energy; protein does not all become muscle. A short-term laboratory result cannot establish an unlimited daily requirement. Meal timing can be useful for practicality, but total intake and consistent training remain central questions.
Do you need a protein supplement?
A shake is a convenient way to fill a gap. It is not a separate biological requirement. Count protein from meals and supplements together: adding 40 g from a shake to an adequate diet is different from using it to correct a low intake. Dairy, eggs, fish, meat, beans, lentils, tofu and other foods can contribute, with different nutrient profiles.
The whole dietary pattern matters
Askow and colleagues compared vegan and omnivorous diets in 40 active young adults during a nine-day exercise intervention. At matched, moderate protein intakes, measured muscle-protein synthesis did not differ between the diets or the tested distributions across meals. This was short-term physiology, not a long-term hypertrophy trial. The study was funded by the Beef Checkoff.
Read the research ↗Protein sources differ in digestibility and essential amino-acid content. That makes diet planning relevant, especially when intake is low or options are restricted. It does not make animal foods compulsory, or a supplement automatically superior to a well-planned diet.
The catch: the goal and the person matter
Muscle size, strength and physical function are related but distinct. Strength also depends on technique and neural adaptation. Studies use different training programmes, durations, body-composition methods and starting diets. A lean-mass change is not always a direct measurement of new muscle tissue.
Older adults, people restricting energy, athletes and people with illness may have different needs. Preserving muscle while losing weight is also a different goal from maximising growth while adequately fed. The often quoted 1.6 g/kg research estimate should not be treated as a limit for every situation.
There are fewer long-term trials of very high intakes than of ordinary training diets. Lack of an extra muscle benefit does not by itself prove harm. Equally, trials in healthy adults cannot settle safety or appropriate targets for someone with kidney disease or another condition requiring dietary management.
How strong is the evidence?
What this means for you
Start with your training, your current diet and your goal. A research reference of 1.6 g/kg/day would equal about 112 g total daily protein for a 70 kg adult. That arithmetic illustrates the scale; it is not an individual target. There is little reason to assume that chasing the largest possible number will produce the largest possible muscles.
Use supplements for convenience if needed, while leaving room for fibre-rich foods, healthy fats, carbohydrate and sufficient energy. If you have kidney disease, a complex medical history, unintentional weight loss or concerns about meeting your needs, seek advice from a clinician or registered dietitian.
Enough protein supports muscle; endlessly more is not the same as endlessly better. The useful intervention is matching intake to need alongside effective training, rather than maximising a label or supplement count.
Research & Sources
Morton and colleagues (2018)
A systematic review, meta-analysis and meta-regression of protein supplementation and resistance-training gains.
Nunes and colleagues (2022)
Systematic review and meta-analysis of protein intake to support muscle mass and function in healthy adults.
Biersteker and colleagues (2026)
Effect of a protein intervention during resistance training in frail community-dwelling older adults: a randomised controlled trial.
Trommelen and colleagues (2023)
The anabolic response to protein ingestion during recovery from exercise has no upper limit in magnitude and duration in vivo in humans.
Askow and colleagues (2025)
Impact of vegan diets on resistance exercise-mediated myofibrillar protein synthesis: a randomised controlled trial.
Evidence reviewed: October 2026. Searches included 2025 and 2026 research as well as relevant older studies. This is an editorial investigation, not an exhaustive systematic review.
Evidence vs Hype explains scientific research for educational purposes and does not provide individual medical diagnosis or treatment.
For a different question about food labels and nutritional quality, read Does Adding Protein Make Any Food Healthier? Muscle-building benefits do not automatically establish the overall quality of a protein-enriched snack.
Serving size and protein source also matter in protein gummies versus shakes; a convenient format does not establish an equivalent muscle-building dose.