How much protein do you actually need to build muscle?
The gym has never had a shortage of protein opinions. Two grams per pound. Shake immediately after training. Never skip casein before bed. Some of this is useful. A lot of it is supplement marketing dressed up as science. Here is what the research actually says.
To build muscle, aim for 1.6 to 2.2 grams of protein per kilogram of bodyweight per day. For a 75kg person, that is 120 to 165 grams. The lower end covers most people most of the time. More than 2.2g per kg adds calories without adding meaningfully more muscle for most people.
Where the 1.6 to 2.2g per kg figure comes from
This range comes from a 2018 systematic review and meta-analysis published in the British Journal of Sports Medicine that pooled data from 49 studies and over 1,800 participants. Its conclusion: protein intakes beyond 1.62g per kg of bodyweight per day provided no additional benefit for muscle mass or strength gains in people doing resistance training.
The 2.2g upper figure exists as a buffer for individual variation and for periods of aggressive calorie restriction — when eating in a deficit, higher protein helps preserve muscle tissue. For most people training normally and eating at or above maintenance, 1.6g per kg is where the meaningful gains happen.
The old "1 gram per pound" rule translates to roughly 2.2g per kg — not wrong, but at the top of the useful range rather than representing a scientific consensus. It also conveniently sells protein powder.
Protein targets by bodyweight
| Bodyweight | Lower (1.6g/kg) | Sweet spot (1.8g/kg) | Upper (2.2g/kg) |
|---|---|---|---|
| 55 kg | 88g | 99g | 121g |
| 65 kg | 104g | 117g | 143g |
| 75 kg | 120g | 135g | 165g |
| 85 kg | 136g | 153g | 187g |
| 95 kg | 152g | 171g | 209g |
If you carry significant body fat, basing protein on your goal weight or lean mass rather than total bodyweight gives a more accurate target.
Protein during fat loss vs muscle building
When building muscle in a calorie surplus, 1.6 to 2.2g per kg is the right range. When losing fat while trying to preserve muscle — what most people are actually doing — push toward the higher end, around 2.0 to 2.4g per kg. A calorie deficit creates a competing demand for protein as an energy source, meaning less is available for muscle repair and synthesis.
Does protein timing matter?
Less than the supplement industry suggests, but not zero. The "anabolic window" — the idea that you must consume protein within 30 minutes of training — has been largely debunked. The window is real but measured in hours, not minutes. Getting protein within two to three hours of training is beneficial. Missing by 45 minutes is not a crisis.
What does matter: distributing protein across the day rather than front- or back-loading it. Muscle protein synthesis appears to be maximised when protein is spread across three to five meals containing at least 3g of leucine — the amino acid most directly responsible for triggering the muscle-building response — which in practice means roughly 30 to 50g of high-quality protein per meal.
Best protein sources
| Food | Protein | Notes |
|---|---|---|
| Chicken breast (cooked) | 31g | Complete amino acid profile |
| Tuna (canned) | 28g | High leucine, low cost |
| Beef (lean mince) | 26g | High zinc and creatine |
| Salmon | 25g | Plus omega-3s |
| Eggs (whole) | 13g | Highest protein quality score |
| Greek yoghurt | 10g | Casein-dominant, slow digesting |
| Tempeh | 19g | Best plant-based option |
| Tofu (firm) | 17g | Complete plant protein |
The thing that limits muscle growth more than protein
Protein is necessary. It is not sufficient. The stimulus for muscle growth is progressive resistance training — lifting weights challenging enough to cause micro-damage to muscle fibres, which then repair larger and stronger. Without that stimulus, additional dietary protein above maintenance needs is used for energy or excreted. No amount of protein turns a sedentary body into a muscular one.
Total calorie intake matters enormously. Building muscle in a significant calorie deficit is possible but slow. For experienced lifters, a modest calorie surplus of 200–300 kcal above TDEE with adequate protein is the most efficient path. Use the TDEE calculator to find your maintenance baseline, then the macro calculator to build your protein, carb, and fat targets around it.