How Much Protein Do You Actually Need to Build Muscle?
5 min read · Updated September 2026
Protein is the one macronutrient with a clear, replicated target for building muscle — and most people either undershoot it or wildly overshoot it chasing diminishing returns.
The number: ~1.6 g/kg/day
The landmark Morton et al. (2018) meta-analysis pooled 49 studies and 1,863 lifters. It found that resistance-training gains in lean mass plateau at about 1.6 g of protein per kg of bodyweight per day — with a confidence range up to ~2.2 g/kg.
For a 75 kg (165 lb) person that’s roughly 120–165 g of protein per day. Beyond ~2.2 g/kg, extra protein doesn’t add more muscle.
Distribution beats a single "anabolic window"
You don’t need to slam a shake within 30 minutes of training. Research suggests spreading protein across 3–4 meals of ~0.4 g/kg each is more effective for muscle protein synthesis than skewing it all to one meal.
What counts
- Prioritize complete proteins: meat, fish, eggs, dairy, and soy.
- Plant-based? Combine sources (legumes + grains) and aim slightly higher, since plant protein is less leucine-dense.
- A simple hand rule: a palm-sized portion of protein at each meal gets most people close.
The catch
Protein only builds muscle in the presence of a training stimulus and adequate total calories. Eating 200 g of protein on the couch won’t do much — pair it with progressive resistance training.
Frequently asked
Can your body only absorb 30g of protein per meal?
You absorb essentially all of it — that myth confuses absorption with muscle-building signaling. Per-meal muscle protein synthesis does plateau around 0.4 g/kg, which is why spreading protein across 3–4 meals beats one giant serving.
Do I actually need protein powder?
No. Powder is just a convenient, cheap way to hit your target. Whole foods (meat, fish, eggs, dairy, soy) work exactly as well.
How much protein to keep muscle while losing fat?
Keep it high in a deficit — around 1.6–2.2 g/kg — to protect lean mass while you lose fat. If anything, protein needs go up slightly when dieting.
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