Recommended Daily Protein Intake for Healthy Adults
For generally healthy adults, consume at least 1.0-1.2 g/kg body weight per day, not the outdated 0.8 g/kg minimum. 1, 2
Standard Adult Requirements
The traditional RDA of 0.8 g/kg/day represents only the bare minimum needed to prevent progressive lean body mass loss, not optimal health. 3, 1, 2 This value was established through short-term nitrogen balance studies and does not address functional outcomes like muscle strength, immune function, or overall vitality. 4, 5
Current evidence-based recommendations for optimal health are:
- Minimal physical activity: 1.0-1.2 g/kg/day 1, 2
- Moderate physical activity: 1.3 g/kg/day 1
- Intense physical activity: 1.6 g/kg/day or higher 1, 2
Age-Specific Adjustments for Older Adults (≥65 years)
Older adults require substantially more protein than younger adults due to decreased protein turnover rates and anabolic resistance. 3, 6 Protein tissue turnover declines from 30% in younger adults to 20% or less by age 70, necessitating higher dietary intake. 6
The European Society for Clinical Nutrition and Metabolism (ESPEN) and Nordic countries recommend:
- Baseline for all older adults: 1.0-1.2 g/kg/day 3, 1, 2
- Older adults with acute or chronic illness: 1.2-1.5 g/kg/day 3, 1, 2
- Severe illness, injury, or malnutrition: Up to 2.0 g/kg/day 1
The higher requirements for older adults are supported by evidence showing improved muscle mass, strength, immune status, wound healing, blood pressure, and bone health with protein intakes above the traditional RDA. 7
Distribution Throughout the Day
Spread protein intake across meals, targeting approximately 0.4 g/kg body weight per meal to maximize muscle protein synthesis. 3 This distribution pattern is particularly important for older adults at risk of sarcopenia and frailty. 3
Safety Considerations
Long-term consumption up to 2.0 g/kg/day is safe for healthy adults, with a tolerable upper limit of 3.5 g/kg/day for well-adapted individuals. 4 However, chronic intake exceeding 2.0 g/kg/day may result in digestive, renal, and vascular abnormalities and should be avoided. 4
Concerns about detrimental effects of increased protein intake on bone health, renal function, or cardiovascular function in healthy individuals are generally unfounded—many of these parameters actually improve with higher protein intake. 7
Practical Implementation
- Calculate using actual body weight, not ideal body weight (unless working with a dietitian for obese patients). 1
- Prioritize high-quality protein sources containing all essential amino acids (lean meat, fish, poultry, eggs, dairy). 3, 1, 4
- Ensure adequate total energy intake, as caloric restriction increases protein requirements. 3, 1
- Monitor body weight to assess adequacy, adjusting for fluid status. 1
Common Pitfalls to Avoid
The 0.8 g/kg/day recommendation is outdated for optimal health and represents only the minimum to prevent deficiency, not the amount needed for maintaining muscle mass, immune function, and overall vitality. 1, 2, 6 This is especially problematic for older adults, where 33% of Irish older adults had protein intakes below even the minimal requirement of 0.66 g/kg/day. 3
Plant-based proteins can meet requirements when consumed in adequate variety and amounts throughout the day, though animal proteins provide higher biological value and essential amino acids more efficiently. 3, 2