05/27/2026
The Recommended Dietary Allowance for protein is 0.8 grams per kilogram of body weight per day. For a 70 kg adult, that is 56 grams. The number has been treated for decades as if it represents an optimal target, the amount everyone should aim for. It does not.
The RDA was established through the National Academies' Food and Nutrition Board and traces to classical nitrogen balance studies. It is designed to identify the lowest intake at which nitrogen losses are matched by intake in approximately 97.5% of the population. In other words, the RDA is the floor below which protein deficiency becomes likely. It is a public health threshold, not a recommendation for physiological optimization.
That distinction matters most for older adults. After roughly age 50, skeletal muscle becomes progressively less responsive to the same dose of dietary protein, a phenomenon researchers call anabolic resistance. The amount of leucine and essential amino acids that triggered a full muscle protein synthesis response at 25 produces a blunted response at 70. To get a comparable signal, older adults appear to need more protein per meal and more across the day.
A 2022 systematic review and meta-analysis by Nunes and colleagues, published in the Journal of Cachexia, Sarcopenia and Muscle, pooled 105 randomized controlled trials in 5,402 participants. Looking specifically at adults aged 65 and older, the authors found that gains in lean body mass clustered between 1.2 and 1.59 grams per kilogram per day. Below that range, gains were smaller. Above approximately 1.6 g/kg, additional protein produced little further benefit in non-resistance-trained populations, though resistance-trained individuals may benefit from somewhat higher intakes.
This is not a directive that every older adult should eat 1.6 g/kg. The Nunes meta-analysis describes where benefits cluster in the available trial data. The optimal intake for a given individual depends on resistance training status, kidney function, total caloric intake, protein source quality, and how protein is distributed across meals. The point is that 0.8 is almost certainly too low for muscle-related outcomes in older adults, and the relevant range sits meaningfully above the RDA.
The intake gap matters because most older adults are not even hitting the floor. A 2019 NHANES analysis by Krok-Schoen and colleagues found that up to 46% of US adults over 71 consumed less than 0.8 g/kg of protein per day. The conversation about whether the target should be 1.0, 1.2, or 1.6 is happening at the academic level while a meaningful share of the population is still below the deficiency-prevention threshold.
For scale, a 70 kg older adult eating 1.4 g/kg would consume around 100 grams of protein per day. A cup of plain Greek yogurt delivers approximately 23 grams. Three large eggs add 18. A 4 oz portion of chicken breast contributes about 30. A 4 oz serving of salmon adds another 28. None of those individual portions is unusual. The challenge for many older adults is appetite, dentition, food cost, and meal frequency, not the math.
The honest takeaway. The 0.8 g/kg RDA is a deficiency-prevention threshold from nitrogen balance studies. It was never designed to optimize muscle outcomes in older adults. Modern evidence points toward 1.2 to 1.6 g/kg as the range where muscle-related benefits cluster in pooled trial data, with the precise individual target still debated. The more urgent gap is that a substantial fraction of older adults are not meeting even the floor.
Nunes EA et al., J Cachexia Sarcopenia Muscle 2022
Krok-Schoen JL et al., J Nutr Health Aging 2019
