How Much Protein Do You Need? The Research
The RDA (0.8g/kg) is a deficiency floor, not a target. Here's what ISSN's position stand and dose-response meta-analyses actually say about protein and muscle.
Fact-checked against peer-reviewed sources. Last updated: September 30, 2026.
The RDA for protein, 0.8g per kg of body weight, is often misread as a target. It's actually a minimum designed to prevent deficiency in sedentary adults, not a number aimed at anyone training or managing body composition.
What the Research Actually Shows
The International Society of Sports Nutrition's 2017 position stand on protein reviewed the available evidence and concluded that 1.4 to 2.0 g/kg/day is sufficient for building and maintaining muscle mass in most exercising individuals. That range falls well above the RDA.
A 2021 dose-response meta-analysis in Nutrition Reviews looked specifically at how muscle mass gains scale with protein intake across a wide range of doses. It found that lean body mass gains continue to increase with protein intake up to around 1.3 g/kg/day, after which each additional increment produces meaningfully smaller returns, roughly a third of the earlier gains per equivalent increase.
That doesn't mean protein above 1.3 g/kg/day is useless. It means the biggest jump in benefit happens getting from RDA-level intake up to roughly 1.3-1.6 g/kg/day, with smaller but real gains continuing beyond that.
Protein Needs During Fat Loss
A separate systematic review and meta-analysis focused on adults with overweight or obesity during weight loss found that protein intake above 1.3 g/kg/day was associated with muscle mass gains even during a calorie deficit, while intake below 1.0 g/kg/day carried a higher risk of muscle loss.
This matters because a calorie deficit alone tends to put muscle tissue at risk, and adequate protein is one of the most effective tools for protecting it.
Setting Your Target
| Goal | Protein target | Basis |
|---|---|---|
| General health, sedentary | 0.8 g/kg | RDA floor, deficiency prevention only |
| Active / fat loss | 1.6 g/kg | Supported by ISSN range and fat-loss-specific research |
| Muscle gain | 1.6-2.0 g/kg | Upper end of ISSN recommended range |
Worked Example
A 68 kg person aiming to build muscle:
``` Protein = 68 x 1.8 = 122g per day ```
That's roughly 122g daily, close to the midpoint of the ISSN's recommended range.
Protein Timing and Distribution
Research on muscle protein synthesis suggests spreading protein across 3-4 meals, roughly 0.25g per kg of body weight per dose (or an absolute 20-40g per meal), is more effective for muscle-building than consuming the same daily total in one or two large meals.
Frequently Asked Questions
Is 2 g/kg of protein necessary for everyone trying to build muscle?
No. Most research shows benefits plateau around 1.6-2.0 g/kg/day for the average exercising individual. Going well beyond that range generally doesn't add meaningful extra muscle-building benefit.
Do older adults need more protein than younger adults?
Some research suggests older adults may benefit from protein intake at the higher end of the ISSN range due to reduced anabolic sensitivity with age, though individual needs vary. See our guide to Mifflin-St Jeor for older adults for related context.
Can too much protein harm healthy kidneys?
Current research does not show that higher protein intake (up to roughly 2-2.2 g/kg/day) harms kidney function in healthy adults without pre-existing kidney disease. Anyone with a kidney condition should consult a doctor before increasing protein significantly.
Sources
- 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. PMC
- Tagawa R, Watanabe D, Ito K, et al. "Dose-response relationship between protein intake and muscle mass increase: a systematic review and meta-analysis of randomized controlled trials." Nutrition Reviews, 2021. Oxford Academic
- Systematic review and meta-analysis on protein intake and muscle mass in adults with overweight/obesity during weight loss, 2024. ScienceDirect
Written by
Rahul Kumar
Independent developer and writer. I build calorie and metabolism calculators and explain the research behind them. I’m not a doctor or dietitian; every article is based on published studies, linked in the Sources section below.
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