Walk into any gym and you'll hear the same gospel: eat 1 gram of protein per pound of bodyweight. For an 80 kg person, that's around 176 grams of protein per day. It sounds scientific. It's confidently stated. But where did this number come from, and is it actually right?

Where the 1g/lb rule came from

The origin is somewhat murky. Early bodybuilding culture adopted very high protein targets partly because protein was associated with muscle, and more was assumed to be better. Some early studies on nitrogen balance in athletes did suggest elevated needs above the sedentary population. Over time, "1g per pound" became shorthand: a memorable, conservative upper bound that got repeated until it became canon.

The problem is that the actual research doesn't support it as a universal optimal target.

What the research actually shows

The most comprehensive meta-analysis on protein intake and muscle gain (Morton et al., 2018, published in the British Journal of Sports Medicine) looked at 49 studies and over 1,800 participants. Their finding: protein intakes beyond 1.62 g/kg of bodyweight per day produced no additional muscle gains. That's roughly 0.73 g/lb, significantly below the commonly recommended 1g/lb.

For an 80 kg person, that means ~130g/day is where gains plateau, not 176g/day. The extra 46 grams are simply oxidised for energy, same as carbohydrates, just more expensive.

When you might need more

The above applies to people eating at or above maintenance. During a caloric deficit, the story shifts. When calories are low, some dietary protein gets used for energy rather than muscle building, which means you need a higher total intake to hit the same net anabolic dose. Most evidence suggests 1.8–2.2 g/kg (0.8–1.0 g/lb) during active weight loss phases to preserve muscle mass.

Older adults also benefit from higher protein targets. Muscle protein synthesis becomes less sensitive to leucine with age, meaning you need a larger dose to trigger the same anabolic response. For people over 50, targeting 1.6–2.2 g/kg is more appropriate.

Protein distribution matters too

Total daily protein is only part of the equation. Research on leucine threshold shows that muscle protein synthesis is triggered by hitting a minimum leucine dose per meal, roughly 2–3 grams. This corresponds to around 20–40 grams of high-quality protein per meal.

Spreading your protein intake across 3–4 meals is more effective than eating the same total amount across one or two. Eating 50g of protein in one sitting doesn't double the muscle-building signal compared to 25g. The body has a ceiling per-meal, and surplus simply gets oxidised.

Practical targets

  • For muscle gain: 1.4–1.8 g/kg (0.65–0.82 g/lb) of bodyweight per day
  • During weight loss: 1.8–2.2 g/kg (0.82–1.0 g/lb)
  • Over 50: 1.6–2.2 g/kg, prioritising protein quality (leucine-rich sources)
  • Per meal: 25–40g of complete protein, 3–4 times per day
The extra protein from 1g/lb versus 0.8g/lb mostly gets burned for energy. The difference in muscle building is negligible. The difference in cost and meal complexity is not.

The takeaway

You almost certainly don't need 1g per pound. For most active people, 0.7–0.9g/lb (1.6–2.0 g/kg) is the evidence-based sweet spot for muscle growth and maintenance. Prioritise hitting that target consistently across meals, and focus on high-quality sources, meat, fish, eggs, dairy, legumes, that provide sufficient leucine per serving.