How much protein does a man over 40 really need?

Men over 40 require 1.6–2.2 g of protein per kilogram of bodyweight per day, roughly double the RDA (0.8 g/kg/day), to counteract anabolic resistance: the age-related decline in muscle protein synthesis efficiency per gram of protein consumed, which means older muscle requires a higher protein signal to generate the same anabolic response as younger muscle (Morton et al., Am J Clin Nutr, 2018).

For a 185-lb (84 kg) man over 40, this translates to 135–185 g of protein per day. Most men significantly underestimate their protein intake and overestimate how much protein their meals contain. A 3-oz chicken breast contains approximately 25 g of protein, to hit 160 g/day requires the protein equivalent of six chicken breasts distributed across meals. The key evidence from Aragon, Morton, and Phillips' work: distributing protein across 3–4 meals of 35–50 g each, rather than consuming it all at once, maximizes muscle protein synthesis because each meal needs to exceed the leucine threshold (approximately 2–3 g leucine per meal) required to activate mTOR-mediated protein synthesis.

Honesty Scale: Solid (1) for the 1.6–2.2 g/kg protein recommendation for men over 40 engaged in resistance training. This is one of the most replicated findings in sports nutrition science.

What to do: Calculate your target: weight in kg × 1.8 g. Distribute across 3–4 meals. Prioritize leucine-rich sources: eggs (2.4 g leucine per 100 g protein), dairy (whey protein has highest leucine density), meat, and fish. If dietary protein is insufficient, whey protein powder is the most evidence-supported supplement for the additional protein signal.

For the full picture, read The Supplementation Deep Dive