Reference
Protein Requirements (RDA)
**Protein Requirements (RDA)** is the minimum daily dietary protein intake — set at 0.8 grams per kilogram of body weight for healthy adults — established to prevent deficiency in the general population, not to support athletic performance or muscle accretion.
How the RDA is determined
The Recommended Dietary Allowance for protein is the minimum amount required to prevent deficiency and is derived from nitrogen-balance studies. Nitrogen balance measures the difference between nitrogen consumed (as protein) and nitrogen excreted: a negative balance indicates a catabolic state, and a positive balance indicates an anabolic state. Nitrogen-balance work continues to test whether the 0.8 g/kg/d figure is sufficient across populations; one such study found that 0.8 g/kg/d did not produce nitrogen balance in minimally active vegan men (Bartholomae & Johnston, Nutrients, 2023, PMID:37513577).
Because the RDA is set at the population level to avert deficiency, it represents a floor rather than a target. It does not account for the additional demands of training, recovery, or the reduced efficiency of muscle protein synthesis seen with age.
Higher intakes for athletes and older adults
Athletes generally require more than the RDA. Endurance athletes, for example, are advised to consume roughly 1.5 to 2 times the amount of protein of the average person to support muscle repair and adaptation (Trail Runner Magazine, Kylee Van Horn, RDN, 2021). For a fuller treatment of intake during training and competition, see the guide on protein for athletes.
Older adults also tend to need more than the baseline figure because of anabolic resistance — the reduced responsiveness of muscle protein synthesis to a given dose of protein (PMID:23558692). The same dose that produces a robust synthetic response in a young adult produces a blunted one with aging, which is why higher intakes are commonly recommended for this group.
Per-meal dosing
Total daily protein matters, but distribution across meals does too, because each feeding must reach a threshold sufficient to stimulate muscle protein synthesis. In a controlled trial, 25 g of potato protein isolate consumed twice daily was effective at stimulating muscle protein synthesis rates in young women (Nutrients, 2020, PMID:32349353), illustrating that a meaningful per-meal dose of a high-quality plant protein can produce an anabolic response.
Protein quality affects how much is needed: a protein with a zero amino acid score yields a net protein utilization of approximately 25%, meaning four times the minimal requirement would be needed to meet protein needs (FAO/WHO, Hegsted). Higher-quality proteins reduce that penalty, which is why amino acid composition and digestibility are weighed alongside raw grams when assessing whether an intake meets requirements.
Related terms