The standard recommended amount of protein is 0.8 g for every kilogram you weigh, every day. For someone who weighs 60 kg, that is 48 g. Harvard Health describes it as the minimum amount you need to keep from getting sick, not the amount you are supposed to eat.1
That figure was never meant to tell you how much protein it takes to hold on to your muscle through your forties, fifties and beyond, or to build more. For those, researchers point higher.
Muscle does not stay put on its own. A review of strength training research by Wayne Westcott puts the loss at 3% to 8% of muscle every decade for adults who are inactive.4
A 2016 review led by Stuart Phillips at McMaster University looked at what protein intake supports healthy ageing, and concluded that at least 1.2 to 1.6 g of high-quality protein per kilogram a day is a better target than the standard amount.2 PROT-AGE, an international expert group, recommends at least 1.0 to 1.2 g per kilogram for people over 65, and 1.2 g or more for those who exercise.3
The strongest evidence on building muscle comes from a review of 49 randomised trials with 1,863 healthy adults, all of them strength training for at least six weeks. People given extra protein gained more strength and more fat-free mass than those who were not.5
The gains levelled off at a best estimate of about 1.6 g of protein per kilogram a day. The researchers were not certain of that point: it could sit anywhere from about 1.0 to 2.2 g. So they wrote that it may be prudent to recommend about 2.2 g for people who want to build the most.5 In other words, 1.6 g is where the average person stopped gaining, and 2.2 g covers the top of the range.
A 2022 review of 74 trials came to the same place. More protein during strength training gave small extra gains in lean mass and leg strength. In adults under 65, the gains were clear at 1.6 g per kilogram or more; in adults 65 and over, they were already clear between 1.2 and 1.59 g.6
Every trial in the 49-trial review had people strength training, so protein on its own is not what it tested. The gains are steady rather than dramatic: the extra fat-free mass from protein averaged about 0.3 kg over those trials, on top of what the training itself built.5
The same review found that extra protein added a little less the older people were.5 That is not a reason to give up on it. It is a reason not to sit at the standard amount and hope, and to pair the protein with training that gives your muscle a reason to grow.
The standard amount of protein keeps you healthy, and holding on to your muscle as you age takes at least 1.2 to 1.6 g per kilogram a day. How much protein to build muscle is higher again, about 1.6 to 2.2 g, and the gains come when you pair it with strength training. Eighty Thirty works out how much protein your body needs and tracks it for you, so you build strength meal by meal. Start with our free macro calculator.
Researchers looking at healthy ageing suggest at least 1.2 to 1.6 g of protein per kilogram of body weight a day.2 An expert group, PROT-AGE, recommends at least 1.0 to 1.2 g for people over 65, and 1.2 g or more for those who exercise.3
In a review of 49 trials of people who strength trained, muscle gains levelled off at a best estimate of about 1.6 g per kilogram a day. Because that point could sit as high as 2.2 g, the authors suggest up to 2.2 g for the most muscle.5
We cannot say from the strongest evidence. The 49-trial review only included people who strength trained, so it does not answer that.5 The 2022 review of 74 trials found its clearest gains in lean mass and strength when more protein went together with strength training.6
Not for keeping or building muscle. The standard 0.8 g per kilogram a day is set to keep you healthy.1 Researchers looking at healthy ageing suggest at least 1.2 to 1.6 g, and up to 2.2 g alongside strength training if you want to build muscle.2,5
About 72 to 96 g a day to keep your muscle, and about 96 to 132 g to build it alongside strength training. The standard amount would be 48 g. Spread it across your meals rather than saving it for dinner, so every meal does its share.
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