The Research-Backed Answer
The most comprehensive meta-analysis on protein and muscle growth (Morton et al., 2018, covering 49 studies and 1,800 participants) found that 1.62g of protein per kg of bodyweight per day is sufficient to maximise muscle protein synthesis for most people who train.
More recent research suggests there may be modest additional benefit up to 2.2g/kg, particularly during a calorie deficit or for more advanced trainees. A practical recommendation is 1.6-2.2g per kg, with the higher end appropriate if you're cutting or highly experienced.
| Goal | Protein Target | Example (80kg person) |
|---|---|---|
| Minimum (sedentary) | 0.8g/kg | 64g/day |
| General fitness | 1.2-1.4g/kg | 96-112g/day |
| Muscle building | 1.6-2.0g/kg | 128-160g/day |
| Fat loss (deficit) | 1.8-2.2g/kg | 144-176g/day |
Does Protein Timing Matter?
Protein timing matters less than total daily intake, if you hit your daily target, the timing is a secondary consideration. That said, distributing protein evenly across 3-5 meals maximises muscle protein synthesis throughout the day, as each meal triggers a spike in MPS that lasts roughly 3-5 hours.
Eating protein around training sessions (within a few hours either side) supports recovery and muscle building. The so-called 'anabolic window' immediately post-workout is less critical than once believed, but protein consumption within a couple of hours is still beneficial.
Best Protein Sources
Complete proteins, those containing all essential amino acids, are most effective for muscle protein synthesis. The best sources are: meat, poultry, fish, eggs, dairy and soy. For plant-based eaters, combining complementary protein sources (rice and beans, hummus and pitta) covers the full amino acid spectrum. Protein supplements like whey are simply convenient, no more effective gram-for-gram than food sources.
Can You Eat Too Much Protein?
For healthy adults, high protein intakes (up to 3.5g/kg/day) appear safe based on current evidence. There's no strong evidence that high protein damages kidney function in people without pre-existing kidney disease. The main practical risk is that very high protein intake may displace other nutrients if it comes at the expense of carbohydrates and fats.
