The protein range is one of the better-supported numbers in this field, and it is quoted so often that the reasoning inside it has been lost.
The band, and what moves you within it
1.6 g/kg is roughly where the dose-response curve for muscle protein synthesis flattens in most trained populations. Below it you are likely leaving adaptation available.
2.2 g/kg is roughly where additional intake stops doing anything detectable.
Between them, what moves you up:
A deficit. Protein’s protective role matters more when energy is scarce. Being lean. Less fat to mobilise means more pressure on lean tissue. High training volume. More damage to repair.
Surplus, moderate training: 1.6 × 80 = 128 g/day
Deficit, lean, training hard: 2.2 × 80 = 176 g/day
Difference: 48 g — about 190 kcal, or one chicken breast
The whole range is about one meal component wide. Getting your total roughly right matters far more than picking the exact multiplier.
Body weight or lean mass
Body weight is fine for most people. At higher body-fat levels it overshoots badly — at 30% body fat, 2 g/kg of total weight is close to 2.9 g/kg of lean mass, which is well past useful.
If you carry substantial fat mass, calculate on an estimate of lean mass or on goal weight.
The thing that actually goes wrong
Not the multiplier. The measurement.
Protein is the macro most often under-logged, because the incidental sources are invisible and portion estimates for meat skew low. Most people who believe they are at 2 g/kg are meaningfully below it.
If you want to fix your protein intake, weigh your protein sources for a week and compare the result with what you had been logging. That single exercise tends to be more informative than any adjustment to the target.
Questions we get asked
How much protein do I need to build muscle?
Roughly 1.6 to 2.2 g per kg of body weight per day covers the useful range for trained lifters. The lower end is defensible in a surplus with moderate training; the higher end is better supported when you are in a deficit, already lean, or training very hard, because protein's role in protecting existing tissue becomes more important as energy availability falls.
Can you eat too much protein?
For healthy kidneys there is no established harm at the intakes lifters use, and the concern traces to studies in people with existing renal disease. The practical cost of overshooting is opportunity: protein displaces carbohydrate and fat, both of which fuel training. Very high protein at the expense of carbohydrate can make hard sessions worse.
Should I calculate protein on body weight or lean mass?
Body weight is fine for most people and lean mass is more defensible at higher body-fat levels, where total-weight calculations overshoot substantially. At 30% body fat, 2 g/kg of total weight is closer to 2.9 g/kg of lean mass, which is past the point of any additional benefit.
Tessa Lindqvist
Contributing writer, nutrition · Stronger by Math
Writes about intake, adherence and what the self-monitoring literature actually supports. Weighs her own food, which is why she is sceptical of estimates — including the good ones.
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