Recommended Daily Protein Intake for Adults
For a healthy 70-kg adult, the minimum protein requirement is 56 grams daily (0.8 g/kg/day), but optimal health outcomes are achieved with 70-84 grams daily (1.0-1.2 g/kg/day). 1, 2
Standard Baseline Requirements
The traditional Recommended Dietary Allowance (RDA) of 0.8 g/kg/day—which equals approximately 56 grams for a 70-kg adult—represents only the minimum needed to prevent progressive lean body mass loss, not optimal health. 3, 1, 2 This recommendation comes from the National Academy of Sciences and has remained unchanged since the FAO/WHO/UNU 2007 guidelines established it through meta-analysis of nitrogen balance studies. 3
However, current evidence strongly supports higher intakes of 1.0-1.2 g/kg/day (70-84 grams for a 70-kg adult) for most healthy adults to optimize health outcomes beyond mere deficiency prevention. 1, 2
Optimal Intake Based on Activity Level
Protein needs should be adjusted based on physical activity:
- Minimal physical activity: 1.0 g/kg/day (70 grams for 70-kg adult) 1, 2
- Moderate physical activity: 1.3 g/kg/day (91 grams for 70-kg adult) 1
- Intense physical activity: 1.6 g/kg/day or higher (112+ grams for 70-kg adult) 1, 2
The International Society of Sports Nutrition supports these higher recommendations for active individuals to maximize muscle protein synthesis and training adaptations. 1
Special Population Considerations
Older Adults (≥65 years)
All older adults require at least 1.0 g/kg/day as a baseline, with most benefiting from 1.0-1.2 g/kg/day. 3, 1 The European Society for Clinical Nutrition and Metabolism (ESPEN) established these higher recommendations because older adults experience anabolic resistance and require more protein to maintain muscle mass and function. 3, 1
For older adults with acute or chronic illness, requirements increase to 1.2-1.5 g/kg/day, and severe illness may require up to 2.0 g/kg/day. 1
Practical Context
Most American men already consume significantly more than the RDA, with median intakes ranging from 1.4 g/kg/day for younger adults to 1.0 g/kg/day for those over 71 years. 4 This suggests that higher intakes are both achievable and commonly practiced in real-world settings.
Safety and Upper Limits
Long-term consumption of 2 g/kg/day (140 grams for 70-kg adult) is safe for healthy adults, with a tolerable upper limit of 3.5 g/kg/day for well-adapted individuals. 5 Chronic intake exceeding 2 g/kg/day should be avoided as it may result in digestive, renal, and vascular abnormalities. 5
Implementation Considerations
- 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 (meat, poultry, fish, eggs, dairy) 3, 1
- Distribute protein across meals, aiming for approximately 0.4 g/kg body weight per meal to maximize muscle protein synthesis 3
- Ensure adequate energy intake, as caloric restriction increases protein requirements 1
Common Pitfalls
The most significant pitfall is adhering strictly to the outdated 0.8 g/kg/day minimum when substantial evidence demonstrates that 1.0-1.2 g/kg/day provides superior health outcomes for muscle maintenance, satiety, weight management, and healthy aging. 1, 6 Another common error is failing to adjust protein intake upward for older adults, who have demonstrably higher requirements due to anabolic resistance. 3, 1