Protein intake: what the research says

Evidence-basedBy the Tozemoon Science Team·Updated October 10, 2026·3 min read·14 peer-reviewed studies

How much protein do you need to build muscle?

Aim for about 1.6 g of protein per kg of bodyweight per day (0.7 g per lb), up to 2.2 g/kg (1 g per lb) when cutting or training hard. Spread it across 3–5 meals of 20–40 g each. Above that, extra protein adds little muscle for most lifters.

Protein intake drives muscle repair and growth. Research points to a daily total of about 1.6 g per kg of bodyweight as the point where extra protein stops adding measurable muscle gains for most lifters.

Protein intake: the key facts in 30 seconds

1Aim for about 1.6 g of protein per kg of bodyweight per day (0.7 g per lb). Up to 2.2 g/kg (1 g/lb) may help some lifters.
2Your daily total matters far more than timing or 'anabolic windows'.
3Spread it over 3–5 meals with 0.4 g/kg each (about 30–40 g for most people).
4Eat on the higher end when dieting — it helps you keep muscle.

How much protein intake do you need? Personal calculator

Your bodyweight

lb(81.6 kg)

Where most of the benefit for lifters sits; above 1.6 g/kg gains flatten.

Your daily protein target

131–180 g

Split across 3–5 meals. Each meal: roughly a quarter of this number.

≈ chicken breasts (6 oz cooked, ≈ 50 g)3.6
≈ whey shakes (1 scoop, ≈ 24 g)7.5
≈ cups of Greek yogurt (≈ 20 g)9.0
≈ large eggs (≈ 6 g)29.9

How to spread it across the day

Breakfast
Start strong
Most people under-eat protein in the morning. Eggs, yogurt or a shake fix this easily.
Lunch & dinner
Anchor meals
A palm-to-hand-sized portion of meat, fish, tofu or legumes at each.
Around training
Within a few hours
A protein meal 1–3 hours before or after is plenty. No need to chug a shake in the locker room.
Before bed
Optional
A slow-digesting protein (casein, cottage cheese) can add to your daily total.

What does protein intake actually improve for lifters?

Outcome	Effect	Evidence	Notes
Muscle growth	Clear boost up to ~1.6 g/kg/day	Strong	Beyond this point, extra protein adds little for most people.
Strength	Small boost	Moderate	Mostly via more muscle; strength is driven primarily by training.
Muscle retention when dieting	Large benefit	Strong	Higher intake protects lean mass in a deficit.
Fullness & fat loss	Helps control hunger	Moderate	Protein is the most filling nutrient per calorie.
Meal timing	Minor effect	Moderate	When total intake is matched, timing barely changes results.

Best protein sources

Meat, fish, eggs, dairy

Kicks in: Complete

+ All essential amino acids, high leucine.

− Can be costly; fattier cuts add calories.

Whey protein

Kicks in: Fast

+ Cheap per gram, convenient, high leucine.

− Some people tolerate lactose poorly — try isolate.

Plant proteins (soy, pea)

Kicks in: Complete when mixed

+ Works similarly when total intake is high enough.

− Slightly less leucine; aim a bit higher or blend sources.

Casein

Kicks in: Slow

+ Digests over hours, good before bed.

− Thicker texture, no clear advantage over whole food.

Protein intake myths: what the evidence actually says

“You can only absorb 30 g of protein per meal.”

False

You absorb nearly all of it; larger doses are simply used over a longer time. A 2023 study found 100 g still increased muscle building over 12 hours.

“High protein diets damage healthy kidneys.”

False

Trials in healthy adults eating well above 2 g/kg show no kidney harm. People with existing kidney disease should follow medical advice.

“You must drink a shake within 30 minutes after training.”

Mostly false

Total daily protein matters far more than the exact timing. Eating protein within a few hours either side of training is enough.

Ready-to-use protein intake protocols

Muscle gain

For: Lifters in a calorie surplus

1Aim for 1.6–2.2 g/kg/day (≈0.7–1 g/lb).
2Split into 3–5 meals of 0.4 g/kg each.
3Include a 30–40 g serving (e.g. casein or cottage cheese) before bed.

Cutting phase

For: Lifters losing fat

1Raise protein to 2.2–2.6 g/kg/day to protect muscle.
2Prioritise lean sources to keep calories in check.
3Keep lifting heavy; protein alone does not preserve muscle.

What do the key studies on protein intake show?

Meta-analysis

A systematic review, meta-analysis and meta-regression of the effect of protein supplementation on resistance training-induced gains in muscle mass and strength ↗

Morton et al., Br J Sports Med, 2018

What they did: Pooled 49 trials with 1,863 participants doing resistance training.
What they found: Extra protein increased gains in muscle mass and strength; benefits plateaued around 1.6 g/kg/day.

For your training: 1.6 g/kg is the number to hit. More is fine but rarely necessary.

Review

How much protein can the body use in a single meal for muscle-building? ↗

Schoenfeld & Aragon, J Int Soc Sports Nutr, 2018

What they did: Reviewed studies on per-meal protein and muscle protein synthesis.
What they found: The body uses more than 20–25 g per meal; about 0.4 g/kg per meal across 4 meals is a good target.

For your training: The '30 g max per meal' rule is a myth. Big meals still count.

Position stand

ISSN position stand: protein and exercise ↗

Jäger et al., J Int Soc Sports Nutr, 2017

What they did: Expert panel review of protein needs for active people.
What they found: 1.4–2.0 g/kg/day is sufficient for most active people; higher may help during dieting.

For your training: Pick a number in this range and hit it consistently.

Safety

High protein intakes are safe for the kidneys of healthy people.
People with existing kidney disease should follow medical advice.
Very high intakes can crowd out carbs and fats you need for training energy.

Protein intake: frequently asked questions

How much protein do I need to build muscle?+

About 1.6 g per kg of bodyweight (0.7 g per lb) per day. A 180 lb lifter needs about 130 g per day.

Is there an anabolic window after training?+

It's much wider than once believed. Eating protein within a few hours before or after training is enough.

Can I build muscle on a plant-based diet?+

Yes. When total protein is high enough, plant protein supports similar gains. Mix sources like soy, pea and grains.

Is too much protein bad for you?+

Not for healthy kidneys. Studies of intakes above 3 g/kg showed no harm in healthy trained people.

Do I need protein shakes?+

No. Shakes are just convenient food. Whole food works just as well.

All sources (14 most cited studies)

Ranked by citations. Metadata from OpenAlex (CC0).

2021 ESC Guidelines for the diagnosis and treatment of acute and chronic heart failure ↗
Theresa A. McDonagh, Marco Metra, Marianna Adamo et al. · European Heart Journal · 2021 · 13,381 citations · Study · Open access
2016 ESC Guidelines for the diagnosis and treatment of acute and chronic heart failure ↗
Piotr Ponikowski, Adriaan A Voors, Stefan D Anker et al. · European Heart Journal · 2016 · 11,449 citations · Study · Open access
2019 ESC Guidelines for the diagnosis and management of chronic coronary syndromes ↗
Juhani M. Knuuti, William C. Wijns, Antti Saraste et al. · European Heart Journal · 2019 · 7,180 citations · Study · Open access
2015 ESC/ERS Guidelines for the diagnosis and treatment of pulmonary hypertension ↗
Nazzareno Galiè, Marc J.C. Humbert, Jean‐Luc Vachiéry et al. · European Heart Journal · 2015 · 6,939 citations · Study · Open access
2016 European Guidelines on cardiovascular disease prevention in clinical practice ↗
Massimo Francesco Piepoli, Arno Wilhelmus Hoes, Stefan Agewall et al. · European Heart Journal · 2016 · 6,471 citations · Study · Open access
Expert consensus document on arterial stiffness: methodological issues and clinical applications ↗
Stéphane Laurent, J. Cockcroft, Luc Van Bortel et al. · European Heart Journal · 2006 · 6,061 citations · Study
2016 ESC Guidelines for the Diagnosis and Treatment of Acute and Chronic Heart Failure ↗
Piotr P. Ponikowski, Adriaan A. Voors, Stefan D. Anker et al. · European Journal of Heart Failure · 2016 · 5,880 citations · Study · Open access
Heart Disease and Stroke Statistics—2013 Update ↗
Alan S. Go, Dariush Mozaffarian, Veronique Lee Roger et al. · Circulation · 2012 · 5,181 citations · Study · Open access
Chronic inflammation in the etiology of disease across the life span ↗
David Furman, Judith Campisi, Eric M. Verdin et al. · Nature Medicine · 2019 · 4,856 citations · Study · Open access
Allergic Rhinitis and its Impact on Asthma (ARIA) 2008* ↗
Jean Bousquet, N. Khaltaev, Álvaro Augusto Cruz et al. · Allergy · 2008 · 4,739 citations · Study · Open access
2014 ESC Guidelines on the diagnosis and treatment of aortic diseases ↗
Authors Task Force Members, Raimund M. Erbel, Victor Aboyans et al. · European Heart Journal · 2014 · 4,466 citations · Study · Open access
2014 ESC Guidelines on diagnosis and management of hypertrophic cardiomyopathy ↗
Authors Task Force Members, Perry M. Elliott, Aris Anastasakis et al. · European Heart Journal · 2014 · 4,338 citations · Study · Open access
Guidelines for the diagnosis and treatment of pulmonary hypertension ↗
Nazzareno Galiè, Marius M. Hoeper, Marc J.C. Humbert et al. · European Heart Journal · 2009 · 3,855 citations · Study · Open access
European guidelines on cardiovascular disease prevention in clinical practice: executive summary ↗
Ian Graham, Dan Atar, Knut Borch‐Johnsen et al. · European Heart Journal · 2007 · 3,755 citations · Study · Open access

Keep reading

Creatine →

How much creatine should you take per day?

Training volume →

How many sets per week should you do per muscle?

Sleep and recovery →

How many hours of sleep do lifters need for muscle growth?

Put the research into practice

Tozemoon is a free workout tracker: log every set, detect PRs and get AI coaching.

Track your training alongside your nutrition →