The 0.8 figure on the back of the nutrition label was never designed to keep you strong.

It was designed to keep you from getting sick. Those are different jobs, and the number that does the first one badly does the second one fine.

Here's the distinction that matters after 40. The Recommended Dietary Allowance for protein, 0.8 grams per kilogram of body weight, came out of nitrogen balance studies: researchers fed people protein, measured what came out, and found the point at which you stop running a deficit. That point is a floor. Cross below it long enough and you start visibly wasting. Sit just above it and you pass the test.

Nobody ever claimed it was the amount that keeps a 55-year-old woman's legs under her. Stuart Phillips and his colleagues made that argument formally in 2016, in a paper called "Protein requirements beyond the RDA", and it's the paper Peter Attia leans on more than any other when he says the RDA is a minimum.

So when Gabrielle Lyon says a gram per pound, when Stacy Sims says 1.4 to 2.2 grams per kilogram, and when Attia says most people should roughly double the RDA, each of them is answering a different question. The answers get mashed into one number by the time they reach your feed.

By the end of this you'll know which question each number answers, which one applies to you, and what to put on your plate tomorrow morning.

---

What actually changes after 40

Two things, and they compound.

The first is anabolic resistance. Aging muscle responds less efficiently to the same protein. A meal that triggered muscle building at 30 gives a weaker signal at 55, so you need a bigger dose to flip the same switch. This is the reason the PROT-AGE Study Group and the ESPEN expert group both set their recommendations for older adults above the RDA rather than at it, and why they specify a per-meal dose, not just a daily total.

The second is estrogen. As it falls through perimenopause, muscle and bone loss accelerate. You're being asked to hold onto lean tissue at exactly the point your body has stopped helping.

The practical result is that the same breakfast does less work than it used to, at the moment you need it to do more.

And the gap between what women eat and what the experts recommend is real, though not in the way it usually gets sold. Almost nobody is below the RDA: in US NHANES data covering nearly 58,000 people, women aged 51 to 70 fell below the RDA somewhere between 7% and 23% of the time depending on the year, and below the estimated average requirement only about 4% to 5% of the time (Berryman 2018).

The interesting number is the other one. In UK national diet survey data on adults over 65, fewer than 15% reached the 1.2 g/kg that expert groups actually recommend (Morris & Jackson 2020).

You're comfortably clearing a 1970s minimum and missing the amount that would keep you strong. [QUOTABLE]

What that costs is measurable. In a cohort of older women followed for three years, those eating at least 1.1 g/kg had dramatically lower odds of frailty than those below it, and mean intake in the group was only 0.96 g/kg (Isanejad 2020). The effect size there is large enough that I'd want a bigger replication before quoting it as gospel, and I'll come back to that.

---

Three numbers, three questions

Here's the framework that resolves most of the confusion. There isn't one ceiling. There are three, and they answer different things.

For a 150-pound woman, that's roughly 109 grams, 95 to 150 grams, and 225 grams.

The first number is the one people misread. Morton's meta-analysis found that gains in muscle mass and strength from protein plus lifting plateau at about 1.6 g/kg per day. That gets quoted as "more than 1.6 is pointless."

It means something narrower. Past that point, the extra protein stops adding measurable muscle in those trials. That's a different claim from saying it harms you, or that it does nothing else useful.

And the paper says something else that almost never survives the trip to a podcast clip.

That 1.62 figure came with a 95% confidence interval running from 1.03 to 2.20 g/kg, so the true plateau could sit anywhere in that band. Morton and his colleagues drew the obvious conclusion themselves: because the interval reaches 2.20, they wrote that "it may be prudent to recommend ~2.2 g protein/kg/d" for people trying to maximize gains from resistance training.

The single most-cited paper for the idea that 1.6 is enough contains its authors recommending 2.2. [QUOTABLE]

---

Where each of them lands

Gabrielle Lyon argues for roughly one gram per pound of ideal body weight, which works out to about 2.2 g/kg. Her case rests on work she was close to: Layman 2003 put women on 1.6 g/kg during weight loss against an RDA-level diet and found more fat loss with lean mass spared. Her per-meal argument comes from Mamerow 2014, where spreading protein evenly across three meals raised 24-hour muscle protein synthesis about 25% compared to the same total loaded onto dinner.

Note what she's dosing on. Ideal body weight, not current weight. A woman carrying significant extra weight who applies a gram per pound to today's scale reading gets a number far higher than Lyon is recommending.

Stacy Sims works the female-specific layer. The ISSN position stand on the female athlete she co-authored puts the range at 1.4 to 2.2 g/kg across the lifespan, with protein distributed every three to four hours rather than banked for one meal. She also points to something most general guidance skips: protein requirements appear to shift across the menstrual cycle, with lysine needs measurably higher in the luteal phase.

Peter Attia sits closer to the middle and reasons from the dose-response curve. Phillips 2016 for why the RDA is the wrong target, Morton 2018 for where the returns flatten, and Nowson and O'Connell 2015 for why aging raises the requirement rather than lowering it.

His name is on this article, so it's worth saying that his protein numbers come from the papers he cites rather than from anything female-specific. He's the reason a lot of women first heard the RDA was too low, and he isn't the person to ask about the luteal phase.

Put the three side by side and the spread is 1.4 to 2.2. That's the actual disagreement. It's much smaller than the internet makes it sound.

---

Your number, and the rule that matters more

Take your weight in kilograms (pounds divided by 2.2) and multiply.

• Not currently training: 1.2 to 1.6 g/kg
• Strength training twice a week or more: 1.4 to 2.0 g/kg
• Losing weight, or on a GLP-1: 1.4 to 2.0 g/kg, and don't go below the top of that range if you're also lifting
• Over 65: hold 1.2 g/kg as your floor, whatever else applies
• Mostly plant-based: add about 15%

If your weight is well above the healthy range for your height, dose on your goal weight rather than today's, or the number inflates past anything anyone is recommending.

The protein calculator does all of this, including the adjusted-weight math, if you'd rather not do it by hand.

Now the part that matters more than your daily total: how you split it.

Muscle protein synthesis is triggered per meal, not per day. In midlife it takes roughly 25 to 40 grams at a single sitting to flip that switch. Three coffees and a 60-gram dinner adds up to a respectable daily number and wastes most of it.

That's the whole finding in Mamerow: same total protein, better distribution, 25% more muscle protein synthesis over 24 hours.

In practice this means breakfast is where most women lose. A bowl of oatmeal is about 6 grams. Getting to 30 usually takes a deliberate change, not a smaller one: Greek yogurt with a scoop of protein powder, three eggs plus cheese, or cottage cheese with nuts.

If you're on a GLP-1, this is more urgent rather than less. Appetite drops so fast that protein is often the first thing to collapse, and a meaningful share of the weight lost can be muscle unless protein and resistance training hold the line. Higher protein during a deficit is what preserves lean mass, and the deficit on these medications can be steep.

---

The kidney question

This is the objection that stops more women than any other, and it's worth taking seriously rather than waving off.

The concern is real in origin. Higher protein does raise glomerular filtration rate, meaning your kidneys work harder. For decades that was read as damage in progress.

Three pieces of evidence say otherwise for healthy kidneys.

A meta-analysis of 28 studies covering 1,358 people found that while higher protein raises GFR, the change in kidney function doesn't differ from normal or low protein diets in healthy adults (Devries 2018). Working harder and being harmed turn out not to be the same thing.

A one-year crossover study kept resistance-trained participants at 2.5 to 3.3 g/kg per day, several times the RDA, and found no harm to kidney function, liver function, or blood lipids (Antonio 2016). That study was in trained men, which limits how far you can carry it, and it's still the longest look anyone has published at intakes that high.

And a 2024 meta-analysis of 148,051 people with 8,746 cases of chronic kidney disease found higher total, plant, and animal protein each associated with lower CKD risk, not higher (Cheng 2024).

The caveat travels with all three, and it isn't small: this applies to people without existing kidney disease. If you have moderate to severe CKD, protein restriction is a real clinical tool and this is a conversation for your nephrologist, not an article.

If you don't know where your kidney function sits, that's a reason to ask for an eGFR at your next blood draw, not a reason to avoid protein.

---

Where this case is weaker than the podcasts admit

The frailty numbers are almost too good. That OSTPRE finding, where women at 1.1 g/kg had roughly a tenth the odds of frailty, is an observational cohort. Women who eat more protein also tend to be women who cook, shop, chew comfortably, and move more. Some of that effect is protein and some of it is everything that travels with protein, and observational data can't fully separate them.

The plateau everyone quotes wasn't statistically significant. Morton's breakpoint analysis rested on 42 study arms and 723 participants, and the model returned p=0.079. The authors published it anyway and said so plainly, which is the right call, but the 1.6 figure that now circulates as settled fact is a soft finding presented honestly and then hardened by repetition.

Most of the dose-response work wasn't done in menopausal women. Morton's meta-analysis pooled resistance training trials that skewed young and male. Antonio's safety study was entirely trained men. We're extrapolating to a population that differs in exactly the hormonal variable that matters here, and Sims is the only one of the three whose evidence base is built on women.

The protein and longevity tension is unresolved. Protein drives mTOR signaling, which builds muscle, and chronic mTOR activation is implicated in some aging pathways. Whether the muscle you gain outweighs anything you might trade is an open question, not a settled one. Anyone telling you it's fully answered in either direction is ahead of the evidence.

Plant-based eating changes the math more than the 15% adjustment suggests. Plant proteins are lower in leucine and lysine and less digestible, which is why the adjustment exists. But among long-term vegans studied recently, about 75% met their total protein target while only 56% met digestible lysine and 43.5% met digestible leucine (Soh 2025). Hitting a gram target and hitting an amino acid target are two different achievements.

None of this changes the direction of the advice. It changes how loudly anyone should state it.

---

What to do this week

1. Work out your number. Weight in kg times 1.2 to 2.0 depending on where you land above. Write it down.
2. Fix breakfast first. It's where the gap almost always is, and it's the easiest 25 grams you'll ever add.
3. Aim for 25 to 40 grams at each of three meals rather than a daily total you hit by accident at dinner.
4. Pair it with lifting. Protein without resistance training is a partial intervention. The dose-response curve in every study above assumed training.
5. Get an eGFR at your next blood draw if you don't know your kidney function.

Everything here is education rather than medical advice, and I'm a medical technologist who reads primary research rather than your clinician. Take the number to someone who knows your labs, particularly if you have kidney disease, are on a GLP-1, or are managing any condition where protein load matters.

If you want your number calculated for you, including the adjusted-weight and plant-protein math, the protein calculator is free and every figure in it links to the paper behind it.

Send this to a friend who's been told her labs are fine and still can't get off the floor without using her hands.

---

Sources

• Phillips SM, Chevalier S, Leidy HJ (2016). Protein requirements beyond the RDA. Appl Physiol Nutr Metab 41(5):565-572. doi:10.1139/apnm-2015-0550
• Morton RW, Murphy KT, McKellar SR, et al. (2018). A systematic review, meta-analysis and meta-regression of the effect of protein supplementation on resistance training-induced gains in muscle mass and strength. Br J Sports Med 52(6):376-384. doi:10.1136/bjsports-2017-097608
• Nowson C, O'Connell S (2015). Protein requirements and recommendations for older people. Nutrients 7(8):6874-6899. doi:10.3390/nu7085311
• Bauer J, Biolo G, Cederholm T, et al. (2013). Evidence-based recommendations for optimal dietary protein intake in older people (PROT-AGE Study Group). JAMDA 14(8):542-559. doi:10.1016/j.jamda.2013.05.021
• Deutz NEP, Bauer JM, Barazzoni R, et al. (2014). Protein intake and exercise for optimal muscle function with aging (ESPEN Expert Group). Clin Nutr 33(6):929-936. doi:10.1016/j.clnu.2014.04.007
• Sims ST, Kerksick CM, Smith-Ryan AE, et al. (2023). ISSN position stand: nutritional concerns of the female athlete. J Int Soc Sports Nutr 20(1). doi:10.1080/15502783.2023.2204066
• Layman DK, Boileau RA, Erickson DJ, et al. (2003). A reduced ratio of dietary carbohydrate to protein improves body composition and blood lipid profiles during weight loss in adult women. J Nutr 133(2):411-417. doi:10.1093/jn/133.2.411
• Mamerow MM, Mettler JA, English KL, et al. (2014). Dietary protein distribution positively influences 24-h muscle protein synthesis in healthy adults. J Nutr 144(6):876-880. doi:10.3945/jn.113.185280
• Kriengsinyos W, Wykes LJ, Goonewardene LA, et al. (2004). Phase of menstrual cycle affects lysine requirement in healthy women. Am J Physiol Endocrinol Metab. doi:10.1152/ajpendo.00262.2003
• Murphy CH, Hector AJ, Phillips SM (2015). Considerations for protein intake in managing weight loss in athletes. Eur J Sport Sci 15(1):21-28. doi:10.1080/17461391.2014.936325
• Devries MC, Sithamparapillai A, Brimble KS, et al. (2018). Changes in kidney function do not differ between healthy adults consuming higher- compared with lower- or normal-protein diets. J Nutr 148(11):1760-1775. doi:10.1093/jn/nxy197
• Antonio J, Ellerbroek A, Silver T, et al. (2016). A high protein diet has no harmful effects: a one-year crossover study in resistance-trained males. J Nutr Metab 2016:9104792. doi:10.1155/2016/9104792
• Cheng Y, Zheng G, Song Z, et al. (2024). Association between dietary protein intake and risk of chronic kidney disease: a systematic review and meta-analysis. Front Nutr 11:1408424. doi:10.3389/fnut.2024.1408424
• Berryman CE, Lieberman HR, Fulgoni VL III, Pasiakos SM (2018). Protein intake trends and conformity with the DRIs among adults in the United States. Am J Clin Nutr 108(2):405-413. doi:10.1093/ajcn/nqy088
• Morris S, Jackson S (2020). Adequacy of protein intake in older adults in the UK. Geriatrics 5(1):6. doi:10.3390/geriatrics5010006
• Isanejad M, Sirola J, Rikkonen T, et al. (2020). Higher protein intake is associated with a lower likelihood of frailty among older women, Kuopio OSTPRE-Fracture Prevention Study. Eur J Nutr 59(3):1181-1189. doi:10.1007/s00394-019-01978-7
• van Vliet S, Burd NA, van Loon LJC (2015). The skeletal muscle anabolic response to plant- versus animal-based protein consumption. J Nutr 145(9):1981-1991. doi:10.3945/jn.114.204305
• Soh BXP, Rutherfurd-Markwick K, et al. (2025). Protein and amino acid adequacy in long-term New Zealand vegans. PLOS ONE 20(4):e0314889. doi:10.1371/journal.pone.0314889

---

Art direction (review notes, not part of the article)

Two images, both to be produced before this publishes.

Image 1. A simple chart with three labeled bands on a horizontal g/kg axis: the muscle plateau at 1.6, the practical working range 1.4 to 2.2, and the tested safety headroom at 3.3. Free-image search: this one has to be built, not found. AI image prompt: "clean editorial data visualization, horizontal axis, three labeled shaded bands in deep teal and warm coral on cream background, minimal serif labels, no clutter, magazine infographic style"

Image 2. Side-by-side plates showing a typical 6-gram breakfast next to a 30-gram breakfast, same dish size, labeled with the gram counts. Free-image search: Pexels or Unsplash, "greek yogurt breakfast bowl natural light" and "oatmeal bowl overhead". AI image prompt: "two breakfast bowls side by side on cream linen, overhead natural window light, one plain oatmeal one greek yogurt with berries seeds and nuts, warm editorial food photography, soft shadows"