How many g of protein per day
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Daily Protein Intake Recommendations
General Population Protein Requirements
The Recommended Dietary Allowance (RDA) for protein in the United States is 0.8 grams per kilogram of body weight per day (g/kg/d) for adults, which is considered the minimum amount necessary to avoid the progressive loss of lean body mass . However, recent studies suggest that this recommendation may be underestimated. Reanalysis of nitrogen balance studies and alternative methods like the indicator amino acid oxidation technique indicate that the mean and population-safe protein requirements are higher, at 0.93 and 1.2 g/kg/d, respectively.
Protein Needs for Physically Active Individuals
For those engaged in regular physical activity, especially resistance training, the protein requirements are significantly higher. The International Society of Sports Nutrition (ISSN) recommends an intake of 1.4 to 2.0 g/kg/d for physically active individuals. This is supported by findings that suggest athletes should consume at least 2.2 g/kg/d to meet their increased protein needs. Long-term consumption of protein at 2 g/kg/d is considered safe for healthy adults, with the tolerable upper limit being 3.5 g/kg/d for well-adapted individuals.
Protein Intake for Muscle Building
For muscle protein synthesis, it is suggested that young adults consume around 20-25 grams of high-quality protein per meal. This amount maximizes muscle protein synthesis, and any excess is likely oxidized for energy or converted to other compounds. To optimize muscle building, a target intake of 0.4 g/kg/meal across at least four meals is recommended, totaling a minimum of 1.6 g/kg/d. For those aiming for higher protein intake, up to 2.2 g/kg/d, the per-meal intake should be around 0.55 g/kg.
Protein Requirements for the Elderly
The elderly may require more protein than the general adult population to maintain muscle mass, strength, and overall health. Evidence suggests that an intake of 1.5 g/kg/d is beneficial for improving muscle mass, immune status, wound healing, and other health factors in elderly individuals. This intake level is higher than the standard RDA and is considered safe and effective for this age group.
Special Considerations for Cancer Patients
Cancer patients undergoing systemic anti-cancer treatment often struggle to meet their protein needs. ESPEN guidelines recommend a minimum protein intake of 1.0 g/kg/d to maintain or restore lean body mass. Studies have shown that high-protein, low-volume oral nutritional supplements can help these patients meet their protein intake recommendations, with significant improvements observed in those who consumed these supplements compared to standard care.
Conclusion
In summary, while the general RDA for protein is 0.8 g/kg/d, this amount is often insufficient for physically active individuals, the elderly, and those with specific health conditions like cancer. For optimal health and muscle maintenance, higher protein intakes ranging from 1.2 to 2.2 g/kg/d are recommended, depending on the individual's activity level and health status.
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