The Confusion Around Protein
No macronutrient generates more debate than protein. RDA values (0.8g/kg) are designed to prevent deficiency, not optimise health. Sports nutrition guidelines start at 1.6g/kg for muscle building. The gap between "sufficient" and "optimal" is where most people are confused.
What the Meta-Analyses Show
A landmark 2018 meta-analysis by Morton et al. (BJSM) examining 49 studies found that protein supplementation significantly increased muscle mass gains during resistance training, with a breakpoint at ~1.62g/kg body weight. Beyond this threshold, additional protein had diminishing returns for muscle building in healthy adults.
For weight loss, higher protein (1.6–2.4g/kg) has strong evidence for preserving lean mass and improving satiety, even without exercise.
Protein for Older Adults
The most underserved population is adults over 65. Sarcopenia (age-related muscle loss) accelerates after 60, and older adults require more protein — not less — to maintain muscle synthesis. Targets of 1.6–2.0g/kg are appropriate and often under-consumed.
Use our Macro Calculator to calculate your personalised protein target based on your goal, weight, and activity level.