How much protein per day, by bodyweight

What people ask us next.

Q01

Is 1 gram per pound of bodyweight the same as 1.6 g/kg?

No, and the difference matters. 1 g/lb works out to ~2.2 g/kg, at the upper end of the Morton 2018 range. It's defensible for aggressive cuts or advanced trainees, but it's above the point of diminishing returns for most lifters. 1.6 g/kg (0.73 g/lb) is the evidence-backed target; 1 g/lb is a round-number heuristic that overshoots without harming.

Q02

How much protein should a 150 lb woman eat?

150 lb = 68 kg. Resistance-trained target: 68 x 1.6 = 109 g/day. Cutting or perimenopausal: push to 68 x 2.0 = 136 g/day. Endurance-only or untrained: 68 x 1.2 = 82 g/day. Kerksick et al. 2018 explicitly extends the ISSN range to trained female athletes without adjustment. The absolute number shifts with bodyweight; the per-kg target does not.

Q03

Is 100 g of protein a day enough?

Depends on bodyweight and goal. For a 60 kg (132 lb) trained lifter, 100 g hits 1.67 g/kg, on target. For an 80 kg (176 lb) lifter, 100 g is 1.25 g/kg, below the Morton 2018 range and likely leaving lean-mass gains on the table. Use the per-kg multiplier, not the round number.

Q04

Does protein need change with age?

Yes, upward. Phillips 2016 and Moore 2015 document anabolic resistance, older adults (50+) require more leucine per dose to clear the MPS threshold. The ISSN and the PROT-AGE consensus (Bauer et al. 2013) recommend 1.2-1.6 g/kg for healthy older adults and up to 2.0 g/kg during recovery from illness or injury. Move the floor up, not the ceiling.

Q05

Is there an upper limit that causes kidney damage?

Not for healthy adults. Antonio et al. 2014-2016 ran trained men at 3.4-4.4 g/kg/day for up to one year with no renal, hepatic, or lipid dysfunction. The renal caution applies only to pre-existing chronic kidney disease (Martin et al. 2005). For healthy adults, 2.2 g/kg is the practical ceiling on performance returns, not a safety limit.

Q06

How does the per-meal dose matter?

Moore 2015 found a per-meal threshold around 0.4 g/kg, roughly 2.5-3 g leucine, to maximally stimulate MPS. For an 80 kg lifter, that's ~32 g protein per meal. Total daily dose drives most of the effect (Schoenfeld & Aragon 2018), but hitting the threshold at 3-4 meals beats front-loading or back-loading a single 80 g bolus.