Protein recommendations range wildly depending on who you ask. Fitness influencers claim you need 2g per pound of bodyweight. The NHS says 50g daily is fine. Who's right?
The answer, backed by peer-reviewed research, lies somewhere in between - and depends on your goals, activity level, and age.
The Official Guidelines
The UK Reference Nutrient Intake (RNI) for protein is 0.75g per kilogram of body weight per day for adults. For a 70kg person, that's about 52.5g daily.
However, this is the minimum to prevent deficiency in sedentary adults - not the optimal amount for health, muscle maintenance, or athletic performance.
| Body Weight | RNI Minimum | Active Adults | Building Muscle |
|---|---|---|---|
| 60kg / 9.5 stone | 45g | 72-96g | 96-120g |
| 70kg / 11 stone | 52g | 84-112g | 112-140g |
| 80kg / 12.5 stone | 60g | 96-128g | 128-160g |
| 90kg / 14 stone | 67g | 108-144g | 144-180g |
Active adults: 1.2-1.6g/kg (International Society of Sports Nutrition). Muscle building: 1.6-2.0g/kg (British Journal of Sports Medicine, 2018).
What the Research Actually Says
A comprehensive meta-analysis published in the British Journal of Sports Medicine (Morton et al., 2018) analysed 49 studies with 1,863 participants. The findings:
- Protein supplementation significantly increases muscle mass and strength when combined with resistance training
- Benefits plateau at around 1.6g per kg of body weight
- Consuming more than 1.6g/kg showed no additional benefit for most people
- For those in a calorie deficit, slightly higher intake (up to 2.0g/kg) may help preserve muscle
Myth: You Can Only Absorb 30g of Protein Per Meal
This is a persistent myth with no scientific basis. Your body will digest and absorb whatever protein you eat - it just takes longer with larger amounts. A 2018 study in the Journal of the International Society of Sports Nutrition found no upper limit to per-meal protein utilisation for muscle building.
Protein Needs Change With Age
Adults over 65 have higher protein requirements. Research published in The American Journal of Clinical Nutrition recommends older adults consume 1.0-1.2g per kg daily to maintain muscle mass and prevent sarcopenia (age-related muscle loss).
This is significant - it means a 70kg person over 65 should aim for 70-84g of protein daily, not the 52g suggested by basic RNI guidelines.
Quality Matters, Not Just Quantity
Not all protein sources are equal. "Complete" proteins contain all nine essential amino acids your body can't produce itself.
Complete Protein Sources:
- Meat, poultry, fish
- Eggs
- Dairy (milk, cheese, yoghurt)
- Soy products (tofu, tempeh, edamame)
- Quinoa
Incomplete Proteins (combine for complete profile):
- Legumes (beans, lentils, chickpeas)
- Nuts and seeds
- Grains
- Vegetables
For plant-based eaters, combining different protein sources throughout the day (not necessarily at the same meal) ensures you get all essential amino acids.
Want to understand more about amino acids? Read our complete guide to the science of amino acids →
"When I design a meal, I'm aiming for 30-40g of protein as standard. That's about a palm-sized portion of chicken, fish, or tofu. It's not complicated - it's just making protein the anchor of the plate."
Practical Takeaways
How Much Protein Do You Need?
- Sedentary adults: 0.8-1.0g per kg body weight
- Regularly active: 1.2-1.6g per kg body weight
- Building muscle: 1.6-2.0g per kg body weight
- Over 65: 1.0-1.2g per kg body weight minimum
- Losing weight: Higher end of range to preserve muscle
References
- Morton RW, et al. (2018). A systematic review, meta-analysis and meta-regression of the effect of protein supplementation on resistance training-induced gains in muscle mass and strength in healthy adults. British Journal of Sports Medicine, 52(6), 376-384.
- Phillips SM, Van Loon LJ. (2011). Dietary protein for athletes: from requirements to optimum adaptation. Journal of Sports Sciences, 29(sup1), S29-S38.
- Bauer J, et al. (2013). Evidence-based recommendations for optimal dietary protein intake in older people. Journal of the American Medical Directors Association, 14(8), 542-559.