A 2023 study fed healthy young men 100 grams of whey in a single sitting and watched their muscles keep building. No ceiling, no plateau, just more synthesis, dose after dose [1]. The result has done serious damage to one of nutrition's most repeated mantras: that your body can only use 25 to 40 grams per meal, and that the rest is, essentially, expensive wee.

That "muscle-full" model ruled gym lore for fifteen years, born from early work showing roughly 0.4 grams of high-quality protein per kilogram of bodyweight was enough to maximally switch on muscle protein synthesis in young adults [2]. The Trommelen study, published in Cell Reports Medicine, complicates the picture. Healthy young men did a single-leg resistance workout, then drank either 0, 25, 50 or 100 grams of whey. Over the next 12 hours, muscle protein synthesis kept climbing with no detectable upper limit, and the supposed 25-gram ceiling, the authors argue, was an artefact of the doses researchers happened to test, not a physiological law [1]. The obsession with hitting an exact magic number at every sitting is mostly folklore.

How much protein you actually need, and who really needs more

The 30-gram question is the wrong one. The right one is: what's your daily total, and what are you trying to do with it?

For a healthy adult doing little more than walking the dog, EFSA's Population Reference Intake is 0.83 grams per kilogram of bodyweight per day, with an Average Requirement of 0.66 grams per kilogram [3]. That's the European floor, covering basic bodily functions; most people in developed countries clear it without thinking.

Train regularly, and the bar lifts. ISSN recommends 1.4 to 2.0 grams per kilogram per day for exercising adults to support muscle protein synthesis and recovery [2], and for physique-focused lifters chasing serious hypertrophy the recommendation climbs to 2.3 to 3.1 grams per kilogram of fat-free mass per day, divided across four or five meals [2].

The most-cited number, 1.6 grams per kilogram, comes from a 2018 meta-analysis of 49 randomised controlled trials covering 1,863 participants. Morton and colleagues found that protein supplementation during resistance training increased muscle strength by about 26 percent and fat-free mass by about 27 percent versus training alone, with no further benefit above 1.62 grams per kilogram per day in trained adults [4].

Older adults need to think about protein differently. Sarcopenia, the age-related loss of muscle and strength, is an underappreciated driver of frailty, falls and loss of independence, and ISSN recommends 1.2 to 1.6 grams per kilogram per day to counter it, well above the EFSA baseline [2]. For a healthy, active adult, 1.6 to 2.0 grams per kilogram is the range with evidence behind it; for a sedentary adult, the EFSA floor is fine.

The kidney myth, finally laid to rest

Every few months, someone online warns that high-protein diets destroy your kidneys. The claim dates from the 1980s, when researchers noticed that protein intake changed how kidneys filtered blood. The leap from "different" to "damaged" was always shaky, and the evidence has been catching up.

A 2018 meta-analysis of 28 randomised controlled trials covering 1,356 healthy adults compared lower-protein and higher-protein diets. The higher-protein group showed a small but statistically significant increase in glomerular filtration rate, a marker of kidney workload rather than damage, with no decline in kidney function over time, even in studies lasting a year or more [5]. Lead investigator Stuart Phillips has been blunt about it: higher protein increases, not decreases, kidney function [6].

The caveat matters. Anyone with diagnosed chronic kidney disease should follow their clinician's advice on protein, since these trials explicitly excluded that population [5][6]. For the rest of us, the kidney myth is exactly that: a myth.

The GLP-1 wildcard: why protein just became a medical issue

Here is where "protein maxxing" stops being a wellness trend and starts becoming a clinical question. GLP-1 and dual GIP/GLP-1 receptor agonists such as semaglutide and tirzepatide have transformed obesity treatment. Semaglutide users in the STEP trials lost around 15 percent of their bodyweight on average [7], and tirzepatide in the SURMOUNT trials typically produces even greater reductions, often 20 percent or more. The catch, buried in the trial data, is that up to 40 percent of the weight lost can be lean mass, not fat [8][7].

A small study presented at ENDO 2025 by Dr Melanie Haines at Massachusetts General Hospital followed 40 adults with obesity, 23 on semaglutide and 17 in a lifestyle programme, for three months. Within the semaglutide group, older age, female sex and lower protein intake each independently predicted greater muscle loss, which in turn blunted improvements in blood sugar control [8].

This is the bit that should worry anyone considering coming off these drugs. Up to 70 percent of GLP-1 users discontinue within the first year, and when they do, the metabolic penalty of lost muscle drives rapid fat regain [7]. The BELIEVE phase 2 trial combined semaglutide with bimagrumab, a muscle-preserving antibody, and produced 17.8 kilograms of weight loss with lean mass preserved over 72 weeks [7].

If you are on, or planning to come off, a GLP-1 drug, protein is no longer optional garnish. Aim for the higher end of the ISSN range, lift weights, and keep training while you remain on the drug. Anyone on a GLP-1 agonist, or considering coming off one, should work through diet, training and tapering decisions with their prescribing clinician; the BELIEVE trial and STEP/SURMOUNT data describe population effects, not individual guidance.

Late-stage protein, and why the trend won't die

Walk into a Coles or a Whole Foods in 2026 and the shelves tell the story. David protein bars cram 28 grams of protein into 150 calories, Chipotle has rolled out a "High Protein Cup", and even non-alcoholic beverage brands are under investor pressure to launch protein SKUs [9]. The market response has clearly moved past the gym fridge, with protein now a category every consumer-goods company wants a slice of, and the numbers confirm it: Innova Market Insights reports a 32 percent year-on-year increase in new food and beverage launches carrying a "high-in-protein" claim between 2023 and 2024 [10], Grand View Research projected the global protein ingredients market to reach $48.77 billion by 2025 [11], and Expo West 2026 was nicknamed "ProteinWest" by trade press, with protein-enhanced everything from chips to coffee to waffles [12]. The thread running through it is the same: protein has crossed from a niche sports-nutrition concern into mainstream packaged food.

Some commentators think the cultural moment has peaked. Mintel's 2026 prediction is that the "maxxing" mindset will shift toward dietary diversity and complementary plant proteins, with fibre, not protein, becoming the next front-of-pack obsession [13][14]. Volume will keep climbing; the maximalist "more is more" framing may already be fading. The science says more protein helps active people, older people and GLP-1 users hit meaningful targets, but it does not save a sedentary person from a bad diet, and it almost certainly does not need to come in ice cream form. The trend will be remembered as the moment nutrition finally took protein seriously, with the necessary footnotes about who, and why.