The Protein RDA Is 0.8 g/kg. Many Scientists Say That Is Not Enough

The protein RDA and a training-oriented protein target answer different questions. The US adult RDA is 0.8 grams per kilogram daily; expert groups working with older adults and exercise populations often discuss higher amounts. Those numbers should be compared with their purpose and population attached. This article focuses on daily totals and how to calculate them, leaving the separate question of meal distribution to the timing article. A larger number is not automatically a better recommendation for someone with medical dietary restrictions.

Check the units before building a menu

Convert body weight to kilograms before multiplying by a grams-per-kilogram reference, then compare the result with actual portion information. An unspecified chicken breast or bowl of yogurt cannot establish a precise protein total. As an arithmetic example, a 70-kilogram person at 1.0 to 1.2 grams per kilogram would be comparing food intake with 70 to 84 grams daily; this is not a prescription for every 70-kilogram reader. Age, training, appetite, illness and kidney-related care affect which reference belongs in the calculation. Choose the reference first, rather than allowing a supplement label to choose it for you.

Where the 0.8 Figure Came From

The Recommended Dietary Allowance for protein in the United States was built on nitrogen balance studies, most of them performed on young, healthy, sedentary adults. Researchers measured how much dietary protein kept nitrogen intake and excretion roughly even, and set the RDA near that balance point with a safety margin.

Nitrogen balance is a blunt instrument. It says little about muscle protein synthesis, physical function, recovery from illness, or the outcomes that matter as people age. Critics note that the method also tends to underestimate requirements because it misses sweat losses and underestimates nitrogen excretion. The number was designed as a floor, not an optimum.

What the PROT-AGE Panel Recommended

In 2013, an international panel of geriatricians and nutrition scientists, the PROT-AGE Study Group, reviewed the evidence and published a position paper in the Journal of the American Medical Directors Association led by Juergen Bauer and colleagues. Their conclusion: adults over 65 should average at least 1.0 to 1.2 grams of protein per kilogram per day, and those who exercise or are otherwise active should aim for 1.2 or higher.

A year later, the ESPEN expert group, publishing in Clinical Nutrition with Nicolaas Deutz as first author, reached a similar verdict: at least 1.0 to 1.2 g/kg for healthy older adults, and 1.2 to 1.5 g/kg for those who are malnourished or facing acute or chronic illness. Neither group found evidence that these higher intakes harm healthy kidneys.

The Rationale: Anabolic Resistance

Why would older muscle need more? The leading explanation is a phenomenon researchers call anabolic resistance. In a younger adult, roughly 20 to 25 grams of high-quality protein at a meal is enough to nearly maximize muscle protein synthesis. In an older adult, the same dose produces a blunted response, and studies suggest closer to 30 to 40 grams may be needed to trigger an equivalent signal.

Aging muscle also extracts a larger share of ingested amino acids in the gut and liver before they ever reach peripheral tissue, and low-grade inflammation raises the rate at which protein breaks down. Layer on shrinking appetites, and many older adults drift well below even the current RDA without noticing.

What About Active Adults?

The RDA was never meant to cover hard training. Reviews of studies in resistance-trained people generally converge on 1.2 to 1.6 grams per kilogram per day as a sensible range for people who train regularly, with sports-nutrition bodies such as the International Society of Sports Nutrition supporting higher intakes still for those pursuing muscle gain. Endurance athletes also break down and rebuild muscle continuously and tend to benefit from intakes above the RDA.

None of this suggests most young, sedentary adults are protein deficient. It does suggest that the single official number, quoted as if it were a ceiling for everyone, underserves two large groups: people over 65 and people who train.

Translating the Numbers to a Plate

• 70 kg sedentary adult: the RDA implies about 56 grams a day, a daily total to compare with measured portions and their food-label protein amounts, rather than an unspecified menu.
• 70 kg adult over 65: expert panels suggest 70 to 84 grams or more, with portions distributed across meals to fit that daily amount.
• 70 kg regular lifter: research reviews commonly point to 84 to 112 grams, distributed so each training day includes several protein feedings.

Spreading protein matters alongside the total. Because the synthesis response to a meal saturates, loading nearly all daily protein into a single dinner leaves other meals underpowered. Most of the practical benefit comes from consistency rather than timing.

Where the Debate Stands

Official bodies have not moved. The RDA remains 0.8 g/kg, and changing it would require new evidence reviews. Meanwhile, the researchers who study aging muscle have largely settled on the higher ranges for their own populations. Population surveys also suggest a meaningful share of older adults, particularly those eating fewer total calories, fail to meet even the current RDA.

It is worth remembering the limits of the evidence. Most support for higher intakes comes from short-term metabolism studies and observational cohorts rather than long randomized outcome trials, and individual needs vary with kidney function, illness, and activity. Higher protein is not automatically better, and people with chronic kidney disease often need tailored targets set by a nephrologist.

For personal advice, consult a registered dietitian or physician. For most healthy adults, though, the emerging consensus is straightforward: the official floor protects you from deficiency, but experts in protein metabolism increasingly recommend more, especially as you age or train.