Most adults need 1.6-2.2 grams of protein per kilogram of bodyweight daily to build muscle effectively. For an 80kg person, that's 128-176 grams per day. Beyond 2.2g/kg, additional protein provides no further muscle-building benefit for most people, though fat loss phases may benefit from intake up to 2.4g/kg to preserve muscle.
If you've ever Googled protein intake, you'll know the advice is all over the place — some say eat as much as possible, others say a little goes a long way. The reality is simpler than the noise. This post cuts through the conflicting claims and lays out exactly what the research says about how much protein your body actually needs.
Key Takeaways
- Optimal range: 1.6-2.2g per kilogram bodyweight daily maximises muscle protein synthesis
- Distribution matters: Spread protein across 4-5 meals with 25-40g per meal for best results
- Quality sources: Complete proteins containing all essential amino acids support muscle building most effectively
- During fat loss: Higher protein (2.0-2.4g/kg) helps preserve muscle mass while losing fat
What Is the Optimal Protein Intake for Building Muscle?
Research pinpoints 1.6-2.2 grams of protein per kilogram of bodyweight daily as the optimal range for muscle building.
A comprehensive meta-analysis found muscle and strength gains increase with protein intake up to 1.6g/kg/day. Benefits continue modestly up to 2.2g/kg for some individuals, but beyond this point, additional protein provides no further muscle-building advantage.
Protein targets by bodyweight:
| Bodyweight | Lower intake (1.6g/kg) | Upper intake (2.2g/kg) | Fat loss phase (2.4g/kg) |
|---|---|---|---|
| 60 kg | 96g | 132g | 144g |
| 70 kg | 112g | 154g | 168g |
| 80 kg | 128g | 176g | 192g |
| 90 kg | 144g | 198g | 216g |
| 100 kg | 160g | 220g | 240g |
How Much Protein Should You Eat Per Meal?
Distribute daily protein across 4-5 meals with 25-40 grams per meal to maximise muscle protein synthesis throughout the day.
A single dose of 20-25g protein maximally stimulates muscle protein synthesis in younger adults. This threshold increases to 30-40g for larger individuals or after leg training.
What Are the Best Protein Sources for Building Muscle?
Complete proteins containing all essential amino acids are most effective — animal sources generally provide superior amino acid profiles.
Top protein sources:
- Chicken breast: 31g per 100g
- Beef (lean): 26g per 100g
- Fish (white): 23g per 100g
- Eggs: 13g per 100g
- Greek yoghurt: 10g per 100g
- Whey protein: 80g per 100g
For vegetarians/vegans: Combine complementary proteins throughout the day and consider plant-based protein supplements.
Do You Need Protein Shakes to Build Muscle?
Protein shakes are not necessary if you can hit protein targets through whole foods, but they provide a convenient option when whole food is impractical.
Research shows no difference in muscle building between protein from shakes versus equivalent protein from food. We generally recommend clients get 70-80% of protein from whole foods.
Does Protein Timing Matter for Muscle Growth?
Protein timing has a modest effect — total daily intake matters more, but post-workout protein within 2-3 hours supports optimal recovery.
The anabolic window myth has been debunked — you don't need protein within 30 minutes post-workout. What matters most is total daily protein intake, followed by even distribution across meals.
“The International Society of Sports Nutrition Position Stand states that protein intakes of 1.4-2.0g/kg/day for physically active individuals is sufficient to support muscle protein accretion.” — Morton et al., British Journal of Sports Medicine (2018)
Should You Increase Protein While Losing Fat?
Yes, increasing protein to 2.0-2.4g/kg during fat loss phases helps preserve muscle mass while in a calorie deficit.
Higher protein intake protects against muscle loss, increases satiety, and has a higher thermic effect (burns more calories during digestion).
Is 100g of Protein a Day a Lot?
For most adults, 100g is moderate rather than a lot — but it's below optimal for muscle building if you weigh more than 63kg.
To put 100g in context, you'd get there with roughly four chicken breasts or a combination of eggs, Greek yoghurt, and a protein shake. It's a reasonable amount of protein by everyday standards — but if you're 75-80kg and training to build muscle, research says you need closer to 120-176g to maximise results.
A common concern is that high protein intake harms the kidneys. For healthy adults with no pre-existing kidney conditions, the evidence doesn't support this. The British Dietetic Association confirms that higher protein intakes — up to the levels recommended for active adults — pose no risk to kidney function in healthy individuals. If you have existing kidney disease, speak to your GP before making significant dietary changes.
How Do I Calculate How Much Protein I Need?
Multiply your bodyweight in kilograms by 1.6 for the minimum daily target and by 2.2 for the upper end of the optimal range.
Here's a worked example: a 75kg person should aim for 120g (75 × 1.6) to 165g (75 × 2.2) of protein per day. That's your personal target range — anywhere within it will support muscle building effectively.
Activity level doesn't dramatically change the per-kilogram target. Whether you train three or five times a week, the 1.6-2.2g/kg range holds. What changes with higher training volume is total calorie need, not protein per se. The main variable that shifts the range is fat loss — if you're in a calorie deficit, aim for the upper end (2.0-2.4g/kg) to protect muscle mass. Keep it simple: bodyweight in kg × 2 is a practical working target for most people.
How Much Protein Does a 70kg Person Need?
A 70kg person needs 112-154g of protein per day for muscle building, spread across 4-5 meals throughout the day.
At 30-40g per meal, that works out to four solid protein meals daily. A practical day might look like this: scrambled eggs and smoked salmon at breakfast (35g), grilled chicken with rice at lunch (45g), Greek yoghurt and a handful of nuts mid-afternoon (20g), and a lean beef or fish dinner with vegetables (45g). That puts you at roughly 145g — comfortably in the optimal range.
If hitting 112-154g through whole food alone feels like a stretch, a single whey protein shake (25-30g) can bridge the gap without over-complicating your diet. The goal is consistency across the week, not perfection every single day.
How much protein do I need to build muscle?
Research supports 1.6-2.2 grams per kilogram of bodyweight daily. For an 80kg person, that's 128-176 grams daily. Higher intake doesn't provide additional muscle-building benefits beyond this range for most people.
Is 100g of protein a day enough to build muscle?
For many people, 100g is below optimal. If you weigh 80kg, research suggests 128-176g for best results. Calculate your target based on your bodyweight using the 1.6-2.2g/kg formula.
How many grams of protein should I eat per meal?
Aim for 25-40g per meal across 4-5 meals daily. This maximises muscle protein synthesis throughout the day rather than concentrating protein in one or two large meals.
Do I need protein shakes to gain muscle?
No. Protein shakes are convenient but not necessary if you can hit your daily targets through whole foods. Many people build excellent muscle without supplements. Use shakes to fill gaps, not as a primary source.
What's the best protein for muscle building?
Complete proteins containing all essential amino acids: chicken, beef, fish, eggs, dairy, and whey protein. For plant-based diets, combine complementary proteins such as rice and legumes to ensure you get the full amino acid profile.
How much protein daily on Mounjaro or GLP-1 medications?
The usual 1.6-2.2g/kg target applies — and becomes more important, not less, because GLP-1 medications can cause significant muscle loss if protein intake isn't sufficient. Aim for the upper end of the range at 2.0-2.2g/kg and prioritise resistance training alongside your medication.
Is too much protein bad for your kidneys?
For healthy adults with no existing kidney conditions, high protein intake within the 1.6-2.4g/kg range has not been shown to cause kidney damage. Research from the British Dietetic Association confirms this. If you have existing kidney disease, consult your GP before increasing protein intake significantly.
Sources
- Morton, R.W. et al. (2018). A systematic review, meta-analysis and meta-regression of the effect of protein supplementation on resistance training-induced gains in muscle mass and strength in healthy adults. British Journal of Sports Medicine, 52(6), 376-384.
- Stokes, T. et al. (2018). Recent Perspectives Regarding the Role of Dietary Protein for the Promotion of Muscle Hypertrophy with Resistance Exercise Training. Nutrients, 10(2), 180.
- International Society of Sports Nutrition Position Stand: protein and exercise. Journal of the International Society of Sports Nutrition, 14(1), 20. (2017)
- British Dietetic Association (2024). Protein and Kidney Function Fact Sheet. bda.uk.com
Dial In Your Protein For Results
Optimal protein intake is 1.6-2.2 grams per kilogram of bodyweight daily, distributed across 4-5 meals. During fat loss, increase to 2.0-2.4g/kg to preserve muscle.
Hitting these targets consistently makes more difference than perfect timing or expensive supplements.
