How much protein do you actually need in a day?
Short version: if you train, somewhere between 1.6 and 2.2 grams per kilogram of bodyweight — roughly 0.7 to 1 gram per pound. Almost everything above the official RDA exists for one reason: muscle. Not survival.
That gap is where the confusion lives. So here's the whole thing, sorted.
Find your number
Your goal | Daily protein | Example: 80 kg / 175 lb |
|---|---|---|
Just not deficient (sedentary) | 0.8 g/kg | ~65 g |
General training, maintaining muscle | 1.6 g/kg | ~130 g |
Building muscle | 1.6–2.2 g/kg | ~130–175 g |
Cutting (protecting muscle in a deficit) | 2.0–2.4 g/kg | ~160–190 g |
Over 40, any goal | at least 1.6 g/kg | ~130 g+ |
Why the RDA misleads everyone
The 0.8 g/kg figure is a floor — the amount that keeps a sedentary person from going deficient. It was never a target for anyone who trains. Most bad protein advice starts by confusing those two things.
For building or keeping muscle, the research converges on about 1.6–2.2 g/kg. The most-cited analysis on the subject found the benefit flattening around 1.6 g/kg — though the data is loose enough that going a bit higher is reasonable insurance, not waste.
The one time "more" actually helps
Cutting. When calories drop, protein is what decides whether the weight you lose is fat or muscle. Push to 2.0–2.4 g/kg in a deficit. This is the single context where eating more protein earns its keep.
Two things people get backwards
Over 40, you need more, not less. Muscle gets less responsive with age, so the floor rises rather than falls.
And no, you don't "max out at 30 grams per meal." That number is the ceiling on the muscle-building signal, not a limit on what your body absorbs — it absorbs nearly all of it. Daily total is what matters.
What to actually do
Pick your number from the table. Spread it across three to five meals if that's easy; don't lose sleep over the timing if it isn't. Then comes the only hard part, the same one as always: hitting it again tomorrow.
Protein is the one macro worth being precise about. Which is the whole point of a number you can log in two seconds instead of one you abandon by Thursday.
Sources: International Society of Sports Nutrition Position Stand (JISSN, 2017); Morton et al. meta-analysis (Br J Sports Med, 2018); ACSM / Academy of Nutrition and Dietetics / Dietitians of Canada joint position; Nutrients review (2025).