How Much Protein People Actually Need, By the Evidence
The official protein RDA has stood since the 1970s. New research on aging and muscle loss suggests it may be far too low for a meaningful share of older adults.
Somewhere between the protein bar aisle and the bodybuilding forums, a simple nutrition number got lost. The official Recommended Dietary Allowance for protein in the United States is 0.8 grams per kilogram of body weight per day, a figure most adults have never heard and most supplement marketing treats as laughably low. It turns out both the marketing and the official number have a point, just not for the same people.
The RDA of 0.8 g/kg is, by design, the minimum intake that prevents deficiency in the overwhelming majority of healthy adults. According to Harvard Health, that figure is not a target for optimal health, it is a floor, and Harvard's own nutrition experts advise a meaningfully higher range for most adults trying to actively maintain muscle and general health.
What the research actually recommends for adults
Harvard's guidance, drawn from its nutrition faculty, suggests most people do better consuming between 1.2 and 2.0 grams of protein per kilogram of body weight each day, which for a 150-pound (about 68 kilogram) person works out to roughly 80 to 136 grams daily. That is a wide range deliberately, since needs shift with age, activity level, muscle mass, and overall health status. The same guidance is clear that there is a ceiling too: exceeding roughly 2 grams per kilogram is not shown to provide extra benefit for the average person and is unnecessary for anyone who is not an elite athlete or bodybuilder under specific training loads.
Crucially, Harvard's reporting on protein excess stresses that quality and source matter as much as quantity. Most people already eating a varied, reasonably balanced diet meet their protein needs without deliberate effort, which is part of why obsessive protein-counting for a person with no specific muscle-building or medical goal adds little.
The aging case for more
Where the evidence gets genuinely interesting is in older adults, and specifically in people already losing muscle mass to sarcopenia, the age-related decline in muscle tissue that accelerates markedly after age 60. A 2025 study using the indicator amino acid oxidation technique, a rigorous method for establishing actual protein requirements rather than estimating them, found the average requirement for older adults with sarcopenia sat at roughly 1.21 grams per kilogram per day, with a recommended intake closer to 1.54 g/kg/day, according to the study published in Frontiers in Nutrition. Both figures sit meaningfully above the general 0.8 g/kg RDA.
The mechanism researchers point to is something called anabolic resistance: as people age, the same amount of dietary protein triggers a smaller muscle protein synthesis response than it would in a younger adult, according to background summarised in a narrative review on nutritional strategies for sarcopenia in Pharmacology Research and Perspectives. In practice this means an older adult may need to eat more protein than a younger adult simply to achieve the same muscle-preserving effect, not because they are less disciplined but because the biology of protein utilisation itself has shifted.
Why this matters beyond the gym
Sarcopenia is not a cosmetic concern. Reduced muscle mass in older adults is linked to falls, slower recovery from illness or surgery, and loss of independence, which is why clinical nutrition researchers have pushed to formalise a higher protein target specifically for this population rather than leaving everyone on the same general-adult recommendation regardless of age. Current clinical guidance summarised across the sarcopenia literature suggests 1.0 to 1.2 g/kg/day for generally healthy older adults, rising to 1.2 to 1.5 g/kg/day, or higher in some formulations, for those managing an existing chronic disease or diagnosed sarcopenia.
None of this is an argument for extreme high-protein eating in younger, healthy people, nor is it a case for protein supplements over food. The research supports getting more protein from ordinary meals, distributed across the day so muscle protein synthesis has repeated opportunities to respond, rather than one large protein-heavy dinner.
This article reports on published research and is not medical advice. People with kidney disease, in particular, should not increase protein intake without medical guidance, since impaired kidneys can struggle to process higher protein loads, and anyone with a chronic condition or on medication should discuss a significant change in protein intake with a physician or registered dietitian before making it.
The RDA was never wrong for what it was built to measure, the floor below which deficiency becomes a real risk. What the newer research adds is a more precise picture of who sits meaningfully above that floor, and increasingly, aging looks like one of the clearest reasons to eat more protein than the decades-old default number implies.
Published in The Outspoken Digest
Read Next
More Nutrition →
Plant Protein Versus Animal Protein: What Actually Matters in a Real Diet
Mar 12, 2026/4 min read
