Ask a room how much protein they need and you will hear three different numbers, because three different questions are hiding inside the one. The answer for someone sedentary is not the answer for someone squatting three times a week, and neither is the answer for someone dieting hard.
The floor that was never a target
The familiar 0.8 grams per kilogram of body weight comes from the Institute of Medicine’s dietary reference intake, set in 2005 to meet the needs of nearly all healthy adults who are not training (Institute of Medicine, 2005). It is a deficiency-prevention floor, not an optimisation target, and if you lift, it was not written for you.
The evidence for trained people clusters higher. Morton and colleagues (2018) combined 49 resistance-training studies and found that roughly 1.6 grams per kilogram per day was enough to maximise muscle gain, with the curve flattening above that. For people in a cut, the range drifts toward 2.0 to 2.4 grams per kilogram, because a higher intake shifts the body’s breakdown toward fat and away from muscle, and protein is also the most satiating macronutrient by a wide margin.
| Situation | Suggested daily protein |
|---|---|
| Sedentary adult | 0.8 g/kg |
| Recreational training | 1.4–1.8 g/kg |
| Serious resistance training | 1.6–2.2 g/kg |
| Fat loss or cutting | 2.0–2.4 g/kg |
| Adults over 50 | 1.2–1.6 g/kg minimum, plus resistance work |
Per kilogram of what
Most research reports protein per kilogram of total body weight, which is the practical version because you already know your weight. If you carry a lot of fat, scaling to lean body mass gives a slightly lower and arguably more sensible figure, since muscle is what uses the protein, not fat. Our body fat percentage calculator gives you that lean-mass number to scale from.
Spread it through the day
Total intake gets the attention, but distribution matters more than most people expect. Moore and colleagues (2009) found that about 20 grams of high-quality protein was enough to maximally stimulate muscle protein synthesis in young men, with 40 grams producing no further benefit. Phillips and Van Loon (2011) summarised that spacing doses roughly every 3 to 5 hours works better than cramming the day’s total into one large dinner.
The typical Western day, a low-protein breakfast, a modest lunch, a huge dinner, leaves the first two meals under the threshold. Moving some dinner protein into the morning is often a bigger practical win than any supplement. Thirty grams at breakfast is roughly three eggs with Greek yogurt, or a scoop of whey over oats. Nothing exotic.
Do you need to hit it exactly
No. Protein targets are forgiving compared with calorie targets. Landing somewhere inside the range matters far more than a precise gram count each day. At 1.5 instead of 1.8 grams per kilogram you will still progress; the difference sits at the margins.
What actually causes trouble is chronic shortfall, say 0.6 grams per kilogram while dieting hard, which shows up as stalled strength, slow recovery and hunger that never settles.
The questions that come up
People worry about kidneys, and in those with healthy kidney function there is no good evidence that these intakes cause harm. Anyone with existing kidney disease is in a different conversation with their doctor. People worry that protein turns to sugar and breaks the diet; it has a modest thermic cost and is glucogenic, but its effect on satiety and muscle retention outweighs that by a long way. People worry plant protein is weaker; it is somewhat less digestible and lower in a few essential amino acids, which you offset by eating a variety of plants and a little more total.
Putting it together
- Pick your target from the table.
The macronutrient calculator runs steps one through four and shows the whole split against your calorie target.
References
- Institute of Medicine (2005). Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids. National Academies Press.