How Much Protein Do You Really Need Per Day?
The government RDA of 0.8 g/kg is a floor — the minimum to avoid deficiency in a sedentary population. If you lift, run, cut, or are over 50, your actual protein target is significantly higher. Here's what the evidence shows.
The core research
In 2017, Morton and colleagues published a landmark meta-analysis of 49 studies covering 1,863 participants in the British Journal of Sports Medicine. They found that protein intake above approximately 1.62 g/kg/day produced no further gains in muscle mass or strength in resistance-trained individuals.1 This is the most-cited number in modern protein science.
The International Society of Sports Nutrition (ISSN) position stand, published the same year, recommends 1.4–2.0 g/kg/day for exercising individuals — a range that captures Morton's finding with margin.2
Your daily target by goal
| Goal | g/kg bodyweight | For a 180 lb (82 kg) person |
|---|---|---|
| Sedentary / general health | 0.8–1.0 | 65–82 g |
| General fitness / occasional exercise | 1.2–1.6 | 98–131 g |
| Muscle building / hypertrophy | 1.6–2.2 | 131–180 g |
| Cutting (preserving muscle during fat loss) | 2.3–3.1 | 189–254 g |
| Older adult (50+) | 1.2–1.6 | 98–131 g |
Why older adults need more, not less
A phenomenon called "anabolic resistance" means that older muscles respond less efficiently to a given protein dose. A 20-year-old might trigger maximal muscle protein synthesis from 20 g of protein — a 70-year-old might need 40 g to hit the same threshold. Practical implication: older adults who eat "normal" protein intakes often under-fuel their muscle maintenance.
How to hit the target
For a 180 lb lifter aiming at 160 g/day, here's a realistic day:
- Breakfast: 3 eggs + Greek yogurt + 1 scoop GROW whey = 45 g
- Lunch: 6 oz chicken breast + rice + broccoli = 45 g
- Snack: cottage cheese + almonds = 20 g
- Post-workout: 1 scoop LEAN isolate + banana = 28 g
- Dinner: 6 oz salmon + sweet potato = 35 g
Total: ~173 g. Easy.
Can you eat too much protein?
In healthy adults, no. Multi-year studies up to 3.4 g/kg/day have shown no adverse effects on kidney function, bone health, or liver markers.3 The old "high-protein ruins kidneys" warning applies specifically to people with existing kidney disease, not healthy eaters.
Related reading
- Protein — The Complete Guide
- Whey vs Isolate: Which Should You Choose?
- Does Protein Timing Actually Matter?
References
- Morton RW, Murphy KT, McKellar SR, et al. 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. 2018;52(6):376-384. PubMed: 28698222
- Jäger R, Kerksick CM, Campbell BI, et al. International Society of Sports Nutrition Position Stand: protein and exercise. Journal of the International Society of Sports Nutrition. 2017;14:20. PubMed: 28642676
- Antonio J, Ellerbroek A, Silver T, et al. The effects of a high protein diet on indices of health and body composition — a crossover trial in resistance-trained men. Journal of the International Society of Sports Nutrition. 2016;13:3. PubMed: 26778925
This guide is for educational purposes and is not medical advice. If you have kidney disease or any chronic condition, discuss protein targets with your physician.