The best protein intake for longevity is roughly 1.2 to 1.6 grams per kilogram of bodyweight a day, with older adults sitting at the higher end rather than the lower. Protein intake targets for longevity purposes differ meaningfully by age, not because older adults need less, but because two separate bodies of research address two different goals. For active adults generally, roughly 1.6 grams per kilogram of bodyweight per day is a well-supported target for muscle-building capacity. For active adults 65 and older specifically, at least 1.2 grams per kilogram per day is the recommended minimum floor to counteract anabolic resistance, a real, well-documented age-related change worth understanding rather than a source of confusing, conflicting numbers.
- ~1.6g/kg/day is a well-supported target for active adults generally, per the ISSN Position Stand.
- At least 1.2g/kg/day is the recommended minimum for active adults 65+, per the PROT-AGE Study Group.
- This 1.2g/kg floor is still meaningfully higher than the general population RDA of roughly 0.8g/kg.
- Protein isn't reduced during a calorie deficit, research supports keeping it high specifically to preserve muscle mass.
Anabolic resistance, explained
Anabolic resistance refers to a reduced ability of aging muscle tissue to build protein in response to a given amount of dietary protein, meaning the same 25-gram serving that triggers a strong muscle-protein-synthesis response in a 30-year-old produces a smaller response in a 70-year-old. This isn't a vague, hand-wavy aging narrative, it's a documented physiological change with real research behind it, and the practical response is straightforward, older adults generally need a higher per-meal protein dose to trigger an equivalent muscle-building response.
This is precisely why protein guidance for older adults gets special attention in the research literature rather than simply defaulting to the same target used for younger, generally active adults, the underlying biology has shifted, and the target should reflect that shift.
Two research bodies, two protein targets
| ISSN Position Stand (2017) | PROT-AGE Study Group (2013) | |
|---|---|---|
| Target population | Active adults generally | Active older adults (65+) specifically |
| Recommended intake | 1.4-2.0g/kg/day (1.6g/kg midpoint) | At least 1.2g/kg/day |
| Primary goal | Muscle-building capacity | Maintenance against sarcopenia |
| Compared to general RDA (~0.8g/kg) | Roughly double | 50% higher, still a genuine floor |
Seeing these side by side makes the honest picture clear, the 65+ figure isn't lower because older adults need less, it's a distinct, more conservative "minimum floor" recommendation addressing a different specific concern, sarcopenia prevention, than the higher, muscle-building-focused target used for the general active-adult population.
Daily protein target calculator
Calculates your target from bodyweight and age, and shows what that looks like split across three meals.
What a protein target looks like in food
A reference amount of roughly 25 grams of protein, a single meal's worth toward a daily target, looks like about 100 grams of cooked chicken breast, 4 large eggs, 100 grams of cooked salmon, or a cup of plain Greek yogurt. Spreading protein intake across several meals, rather than loading it all into one, is generally a more effective way to consistently trigger muscle protein synthesis throughout the day, particularly relevant given the anabolic resistance pattern in older adults.
The leucine threshold, and why distribution beats daily total
Muscle protein synthesis isn’t proportional to how much protein you eat. It is triggered when a meal delivers enough of one amino acid to cross a threshold, and understanding that changes how you distribute intake rather than just how much you consume.
Leucine as the trigger
Leucine activates mTOR, the signalling pathway that initiates muscle protein synthesis. Below roughly 2 to 3 grams of leucine in a single meal, the response is weak regardless of total protein. Above it, synthesis is stimulated near-maximally, and adding more produces diminishing returns within that meal.
In practical terms this corresponds to roughly 20 to 30 grams of high-quality protein for a younger adult, and closer to 30 to 40 grams for an older one.
Why older adults need more per meal
Anabolic resistance means the same leucine dose produces a smaller synthetic response with age. The threshold rises. This is why an older adult eating the same daily total spread the same way can still lose muscle: several of their meals may be falling below the trigger point entirely.
The distribution problem
A typical Western eating pattern is skewed: a low-protein breakfast, a moderate lunch, and a large dinner. Someone eating 100 grams daily as 10, 25 and 65 grams may only cross the threshold twice, and the excess at dinner can’t be banked.
Three or four meals each clearing the threshold produce more total daily synthesis than the same protein concentrated into one or two. The correction is usually breakfast, which is where most people's shortfall sits.
Protein quality, and what it means for plant sources
Leucine content varies by source. Whey is roughly 10 to 11 percent leucine; most animal proteins sit around 8 percent; many plant proteins fall between 6 and 8 percent, and several are limited in specific essential amino acids.
The practical consequences for a plant-based diet are that per-meal quantities need to be higher to hit the same leucine dose, and that variety across the day matters for covering the full amino acid profile. Soy, lentils and quinoa are among the better options; combining sources across a day handles the rest.
How this maps to the daily target
Common targets of 1.2 to 1.6 grams per kilogram of bodyweight are for the day as a whole. Divided across three or four meals, the per-meal quantity lands naturally near the threshold for most people, which is the real reason the recommendation to spread intake appears alongside the daily number rather than instead of it.
The growth-signalling tension, and why protein is genuinely contested
Everything above treats more protein as straightforwardly better with age. There is a real counter-argument, and it deserves stating properly rather than being waved away, because it comes from the same body of research that underpins much of longevity science.
mTOR and IGF-1
Dietary protein, and leucine in particular, activates mTOR. That is the nutrient-sensing pathway which tells cells to grow and build rather than to repair and recycle. It is exactly the pathway rapamycin suppresses to extend lifespan in mice, and the same axis growth hormone acts on.
Protein intake also raises IGF-1, insulin-like growth factor 1. Across species, reduced IGF-1 signalling is associated with longer life. Some of the longest-lived laboratory mouse strains carry disrupted growth hormone receptors and correspondingly low IGF-1, and in humans, people with Laron syndrome, who can’t produce IGF-1 normally, show strikingly low rates of cancer and diabetes.
So the honest version of the tension is this. The signal that builds muscle is the same signal that, chronically elevated, is associated with faster biological aging in animal models. Protein isn’t a free good.
Where the tension resolves, and where it doesn’t
Two things keep this from being a straightforward argument for eating less protein. The first is that the mTOR and IGF-1 findings come overwhelmingly from animals and from rare human genetic conditions, not from trials in healthy adults eating ordinary diets. The second is that low protein intake in older adults has a documented, immediate downside: accelerated muscle loss, and with it falls, frailty and loss of independence.
That produces a genuine age-dependent split in the literature. Observational work has found higher protein intake associated with worse mortality outcomes in middle age, and with better outcomes after roughly 65. Whether that reflects real biology or the difficulty of separating protein from everything else in a dietary pattern isn’t settled.
My own read is that the sarcopenia risk is concrete, measurable and near-term, while the growth-signalling risk is mechanistically plausible and largely unquantified in healthy humans. That asymmetry is why the targets on this page lean toward adequacy rather than restriction. It is a judgement, not a settled finding, and it is worth knowing which is which.
Methionine, and why the source matters
Methionine restriction extends lifespan in rodents, independently of total calorie intake. Methionine is a sulphur-containing amino acid found in substantially higher concentrations in animal protein, particularly meat and eggs, than in most plant sources. Legumes are notably low in it.
This is one mechanistic route by which plant and animal protein might differ for longevity purposes beyond their amino acid completeness. It is also a reason the plant-versus-animal question isn’t fully answered by comparing leucine content, which is how the comparison is usually framed.
The practical implication is modest and worth stating plainly. Meeting your target with a meaningful share coming from legumes, soy and other plant sources gives you the muscle-preserving benefit while lowering methionine load, without requiring you to eat less protein overall. Whether that translates into a real longevity difference in humans hasn’t been demonstrated.
Working out your own target
Most coverage repeats a single flat protein number regardless of age or activity level, which misses the evidence-based reason the target shifts for older adults.
Calculate from your own bodyweight. Roughly 1.6g/kg/day if you are under 65, and at least 1.2g/kg/day as a floor if you are 65 or older.
Spread intake across several meals rather than one large serving, and keep it high during a calorie deficit specifically to protect lean mass while you lose fat.
Not everyone agrees with these numbers. Valter Longo’s protocol sets protein roughly half as high, and the longevity diet entry sets out both sides of that disagreement.
The app calculates your protein target from your own age and weight, not a flat number.
Sources
Key references for the claims on this page. Where a figure is attributed to a specific study or body, it is named here.
- Jäger R, Kerksick CM, Campbell BI, et al. International Society of Sports Nutrition position stand: protein and exercise. Journal of the International Society of Sports Nutrition. 2017;14:20. 1.4 to 2.0 g/kg/day for active adults. DOI
- Bauer J, Biolo G, Cederholm T, et al. Evidence-based recommendations for optimal dietary protein intake in older people: a position paper from the PROT-AGE Study Group. JAMDA. 2013;14(8):542–559. Approximately 1.2 g/kg/day minimum for older adults. for active older adults, reflecting age-related anabolic resistance.
Frequently asked
What is the best protein intake for longevity?
Around 1.2 to 1.6 grams per kilogram of bodyweight daily for most active adults, with the app calculating your specific target from your own weight and age. Older adults sit at the higher end because anabolic resistance means the same dose produces a smaller response, and spreading it across meals matters as much as the daily total.
What is anabolic resistance?
A reduced ability of aging muscle to build protein from a given amount of dietary protein, requiring more per meal to trigger the same response.
How much protein do you need per day?
Considerably more than the minimum RDA if you are training or older, with common targets sitting around 1.2 to 1.6 grams per kilogram of bodyweight. The entry covers how Longevity Coach IQ calculates your specific target.
Do older adults need more protein?
Yes, which is counterintuitive. Anabolic resistance means aging muscle responds less to the same dose, so older adults need more per meal to trigger the same muscle-building response.
Is too much protein bad for your kidneys?
In people with healthy kidneys there is no good evidence of harm from higher intakes. This concern originates in advice for people with existing kidney disease, where it does apply.
Is plant protein as good as animal protein?
Plant sources are generally lower in leucine and less complete, so slightly higher totals and more variety compensate. A well-constructed plant-based diet reaches the same targets; it takes more attention.
Should you spread protein across meals?
Yes. Per-meal dosing matters more with age because of anabolic resistance, so three or four meals containing meaningful protein beats one large evening serving with the same daily total.