If you do strength training: at least 1.2 g protein per kg body weight per day.[1] For maximal muscle gain, a meta-analysis puts the tipping point at about 1.6 g/kg.[2] Per meal, older adults need around 40 instead of 20 g for the same muscle stimulus.[3] These are guide values from studies that often examine older groups.
Is the general recommendation enough after 40?
The standard recommendation is 0.8 g protein per kg body weight per day. For healthy older adults, a review recommends 1.0 to 1.2 g/kg to preserve muscle mass.[4] That is the dose for maintenance, not for active muscle building.
For active, strength-training older adults, the PROT-AGE position paper names at least 1.2 g/kg with no defined upper limit. It mentions values around 2.0 g/kg only for severely ill or malnourished people.[1] The paper applies to older people in general. For 40- to 55-year-olds there are fewer direct studies.
How much protein do you need to build muscle?
A meta-analysis of 49 studies found a tipping point for strength trainers at about 1.6 g/kg per day. The confidence interval is wide (1.0 to 2.2 g/kg), so 1.6 is not a hard ceiling.[2] A review on muscle building in trained people recommends 1.6 to 2.2 g/kg.[5]
Example at 80 kg body weight: 1.2 g/kg is 96 g of protein a day, 1.6 g/kg is 128 g.
Why do you need more per meal?
With age, muscle becomes less sensitive to protein. Researchers call this anabolic resistance. In younger people about 20 g of protein maximally stimulates muscle protein synthesis; in older people it takes around 40 g.[3] Another review puts the extra need per meal at about 68%.[6]
For masters athletes aged 40 and over, authors name 0.4 to 0.5 g/kg per meal, which is 32 to 40 g at 80 kg.[5] According to the review, the amount matters, not timing or protein source.[3] The studies do not show at exactly what age the effect starts.
How to put it into practice
Spread your protein over three to four meals of roughly 30 to 40 g each. As a rough guide: 150 g chicken breast gives about 35 g, 250 g low-fat quark about 30 g, four eggs about 25 g.
If you have a chronic condition, especially a kidney condition, clear higher protein amounts with your doctor first.
In short
- With strength training: at least 1.2 g protein per kg body weight per day.
- For maximal muscle gain the tipping point is about 1.6 g/kg, with no hard ceiling.
- Per meal, about 40 g (0.4 to 0.5 g/kg) makes sense, not just 20 g.
- Amount matters more than timing or protein source.
Frequently asked questions
Are 20 g of protein per meal enough?
For younger people about 20 g is enough to stimulate muscle protein synthesis maximally. For older adults it is around 40 g.[3]
Do I need protein shakes?
No. According to the review the amount counts, not the source.[3] Shakes are a convenient way to reach the amount, but not a must.
Is more than 1.6 g/kg pointless?
Not necessarily. 1.6 g/kg is a tipping point in the meta-analysis, but statistically not a hard limit. The confidence interval reaches up to 2.2 g/kg.[2]
Do these values apply at 40?
Many studies examine older groups. For masters athletes aged 40 and over there are recommendations from a review,[5] but direct studies of 40- to 55-year-olds are rarer. Treat the values as guidance.
Sources
- Bauer, J., Biolo, G., Cederholm, T., et al. (2013). Evidence-Based Recommendations for Optimal Dietary Protein Intake in Older People: A Position Paper From the PROT-AGE Study Group. Journal of the American Medical Directors Association, 14(8), 542–559. PubMed 23867520Study type: Position paper of an international expert group
- Morton, R. W., Murphy, K. T., McKellar, S. R., 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. doi:10.1136/bjsports-2017-097608Study type: Meta-analysis and meta-regression, 49 studies
- Churchward-Venne, T. A., Holwerda, A. M., Phillips, S. M., & van Loon, L. J. C. (2016). What is the Optimal Amount of Protein to Support Post-Exercise Skeletal Muscle Reconditioning in the Older Adult? Sports Medicine. doi:10.1007/s40279-016-0504-2Study type: Narrative review
- Harris, S., DePalma, J., & Barkoukis, H. (2025). Protein and Aging: Practicalities and Practice. Nutrients, 17(15), 2461. doi:10.3390/nu17152461Study type: Narrative review
- Jahan-Mihan, A., El Khoury, D., Brewer, G. J., & Chapleau, A. (2025). Protein Intake for Muscle Hypertrophy in Resistance-Trained Adults: A Review. Nutrients, 17(22), 3528. doi:10.3390/nu17223528Study type: Narrative review
- Deane, C. S., Cox, J., & Atherton, P. J. (2024). Muscle anabolic resistance in ageing and its implications for protein requirements. Frontiers in Nutrition, 11, 1419229. doi:10.3389/fnut.2024.1419229Study type: Review
Limits of these statements: The recommendations come mostly from reviews and a position paper, partly for groups older than 40 to 55. They do not replace individual nutrition advice, especially not when you have a medical condition.
Note: This article is for general information and does not replace medical advice, diagnosis or treatment. Talk to your doctor before you start training, especially if you have pre-existing conditions.