How Much Protein Do You Actually Need? Setting Evidence-Based Targets for Different Goals

The official RDA (Recommended Dietary Allowance) for protein is 0.8g/kg bodyweight per day. This figure describes the minimum amount sufficient to prevent nitrogen deficiency in sedentary adults. It is not a recommendation for optimal health, muscle preservation, or body composition. Applying the RDA to anyone who exercises or is in a caloric deficit produces systematically insufficient protein intake.

What Protein Targets Are Based On

Protein requirements vary by:

• Training status and goal (resistance training increases the rate of muscle protein turnover, requiring more dietary protein)
• Caloric context (in deficit, dietary protein must also cover gluconeogenic demands; the protein requirement is higher)
• Body composition (leaner individuals have a higher ratio of lean mass to total body mass; requirement scales with lean mass)
• Age (older adults show "anabolic resistance" — blunted mTOR and MPS responses per gram of protein — requiring higher per-meal and per-day protein to achieve the same muscle protein synthesis)

The Evidence-Based Targets

Sedentary adults (maintenance, no training): 1.0–1.2g/kg bodyweight. Slightly above RDA — the RDA underestimates requirements even for sedentary individuals when quality of protein is considered.

Recreational resistance trainees (muscle maintenance + general health): 1.6–2.0g/kg bodyweight. The comprehensive meta-analysis by Morton et al. (2018) found that the dose-response plateau for muscle mass accretion saturated at approximately 1.62g/kg/day — with no additional benefit beyond this threshold in the aggregate. Note: this is the mean; individual variation exists.

Active fat loss / caloric deficit: 2.0–2.5g/kg bodyweight. Higher protein in deficit serves anti-catabolic functions (preserving lean mass) in addition to anabolic ones. The Helms et al. (2014) recommendations for lean resistance-trained athletes in deficit: 2.3–3.1g/kg fat-free mass.

Older adults (60+): 1.6–2.2g/kg bodyweight — higher than younger adults due to anabolic resistance. The rising threshold means the muscle protein synthesis response to a given dose is blunted; higher doses partially compensate.

> 📌 Morton et al. (2018) meta-analyzing 49 RCTs found the dose-response relationship between protein intake and lean mass gain in resistance training plateaued at 1.62g/kg/day (95% CI: 1.03–2.20g/kg). Beyond this point, additional protein added no significant lean mass benefit in the aggregate — but the upper confidence interval suggests individual responders may benefit from higher intakes. [1]

Per-Meal Leucine Threshold

Beyond daily totals, the per-meal leucine threshold matters:

• Each protein meal must contain approximately 2–3 g (0.1 oz) of leucine to maximally stimulate mTOR and muscle protein synthesis
• This typically requires approximately 25–40 g (1.4 oz) of protein per meal from quality sources (whey, chicken, fish, eggs)
• Distributing protein across 3–5 meals of adequate per-meal dose is superior to concentrating it in 1–2 large meals

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Key Terms

• RDA (Recommended Dietary Allowance) — the minimum intake sufficient to prevent deficiency in 97.5% of sedentary adults; appropriate for assessing deficiency risk, not optimal for performance or body composition in exercising populations
• Anabolic resistance — the reduced muscle protein synthesis response to a given protein dose in older adults; caused by impaired leucine sensing, mTOR signaling, and satellite cell activation; compensated for by higher per-meal protein doses (~40 g (1.4 oz)) and higher daily totals
• Leucine threshold — the minimum leucine dose per meal required to maximally stimulate mTOR C1 and muscle protein synthesis; approximately 2–3 g (0.1 oz) of leucine (corresponding to ~25–40 g (1.4 oz) of quality protein); meals below this threshold produce submaximal anabolic response
• Nitrogen balance — the difference between protein intake and nitrogen excretion; positive in surplus + training, zero at maintenance with adequate protein, negative in deficit without adequate protein intake; the biochemical basis for higher protein requirements in caloric restriction

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Scientific Sources

• 1. Morton, R.W., 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. PubMed