How Much Protein Do You Really Need? What the Evidence Shows

The evidence in one number

A widely cited systematic review and meta-analysis pooling data across dozens of resistance training studies found that muscle mass gains plateaued at a protein intake of roughly 1.6 grams per kilogram of bodyweight per day, with intakes beyond that point showing no additional benefit for muscle growth in the pooled data.

That is meaningfully lower than the 2–3+ g/kg figures sometimes marketed alongside protein supplements, and it's a range most people training seriously can reach through food alone.

Why the higher numbers persist anyway

A few reasons the "more protein, always" message keeps circulating despite the evidence:

• Individual variation exists. The meta-analysis found a plateau on average — some individuals in the underlying studies may have benefited from more, particularly during aggressive calorie deficits, where higher protein intakes help preserve lean mass.
• It's a safe recommendation to over-deliver on. Excess protein (within normal dietary ranges) isn't harmful for most healthy people, so "just eat more" is low-risk advice to give even where it isn't necessary.
• It sells products. Protein powder is one of the easiest supplements to market around a number that sounds authoritative, whether or not that number reflects where the actual benefit stops.

What this looks like in practice

For a 75kg lifter, 1.6 g/kg works out to 120g of protein per day — roughly four meals containing 25–30g of protein each (a large chicken breast, a cup of Greek yogurt with a scoop of protein powder, or two eggs with a serving of cottage cheese are all in that range).

The goal isn't to hit the highest number you can reach. It's to hit a sufficient number consistently, without protein intake crowding out the calories needed to actually recover from training.

The exception worth knowing

During a calorie deficit (intentional fat loss), protein needs shift upward — a range closer to 1.8–2.2 g/kg is better supported in the literature for preserving lean mass while in a deficit, since the body's protein requirements to maintain tissue rise when overall energy availability drops. This is one of the few well-supported cases where "more than maintenance level" genuinely applies.

The takeaway

For most people training for strength or muscle gain in a calorie-maintenance or surplus, 1.6 g/kg per day covers what the evidence actually supports. Consistency in hitting that number across most days matters far more than chasing a higher one.