Why the answer is a range, and why the RDA is the wrong anchor
The 0.8 g/kg figure most people have heard is the Recommended Dietary Allowance, and it means something specific: the intake sufficient to meet the requirement of 97.5% of healthy adults. It is a floor for preventing deficiency in a sedentary population, derived largely from nitrogen-balance studies. It was never intended to describe the intake that best supports training adaptation, muscle retention during a diet, or muscle maintenance in later life.
Once you ask those questions, the numbers move. The International Society of Sports Nutrition's position stand on protein and exercise recommends 1.4 to 2.0 g/kg for building and maintaining muscle in physically active people, and notes that higher intakes may be warranted for those in a caloric deficit. The commonly used training band of 1.6 to 2.2 g/kg sits inside that guidance, and the meta-analytic evidence suggests the benefit of additional protein for muscle gain flattens out somewhere around 1.6 g/kg for most people, with individual variation above it.
The highest published figures come from a different question again: how much protein does a lean athlete need in an aggressive deficit to hold on to muscle? Here the recommendations reach 2.3 to 3.1 g per kilogram of fat-free mass, and the basis matters — applying that factor to total body weight in someone with 30% body fat produces a target far above what the authors intended.
Older adults are the other group where the RDA is a poor guide. Muscle protein synthesis becomes less responsive to a given dose with age, so expert groups have recommended 1.0 to 1.2 g/kg for healthy older adults, with more for those who are ill or resistance training.
Body weight or lean mass, and how to split the day
Which mass you multiply matters most at the extremes of body composition. For someone at 15% body fat the two bases differ by 15%, which is inside the width of every band on this page. For someone at 40% body fat they differ by 40%, and using total body weight sets a target driven by adipose tissue that does not use amino acids the way muscle does. The practical rule: use total body weight unless body fat is high or the factor was published on a fat-free basis.
Distribution across the day is a second, smaller lever. Muscle protein synthesis responds to a dose of protein in a saturable way, and the dose that maximises the response in most studies is in the region of 0.4 g per kilogram of body weight per meal — about 32 g for an 80 kg person. Reaching a daily total through three or four such meals produces a better synthetic response than the same total taken in one or two.
Protein quality is the third lever, and it matters most when total intake is modest. Leucine content and digestibility drive the response, so animal proteins and soy reach the threshold at a smaller dose than most single plant sources. Combining plant sources across a day covers the amino acid profile, and adding roughly 10 to 20% to the total is a common practical adjustment for a wholly plant-based diet.
Worked example: an 82 kg lifter eating 2,600 kcal
- Choose the band. Resistance training and muscle gain: 1.6 to 2.2 g/kg.
- Bottom of the range. 82 × 1.6 = 131.2 g.
- Top of the range. 82 × 2.2 = 180.4 g.
- Mid-point. (131.2 + 180.4) ÷ 2 = 155.8 g a day.
- Per meal. 155.8 ÷ 4 = 38.9 g, comfortably above the 0.4 g/kg per-meal reference of 82 × 0.4 = 32.8 g.
- Energy cost. 155.8 × 4 = 623 kcal, which is 623 ÷ 2,600 × 100 = 24.0% of the day's calories.
Now see what happens when this person diets. Drop intake to 2,000 kcal and hold the protein target: 623 ÷ 2,000 × 100 = 31.2% of calories. Nothing about the protein changed, but the percentage jumped by seven points — which is exactly why setting protein as a percentage rather than in grams per kilogram silently cuts your protein whenever you cut your calories.
What does 155.8 g actually look like? Roughly 170 g of cooked chicken breast supplies about 50 g, a 200 g pot of Greek yoghurt about 20 g, three eggs about 18 g, and a 30 g scoop of whey about 24 g. Four meals of that shape reach the target without difficulty; the same target from lentils and rice alone takes noticeably more planning and volume.
To turn the remaining 1,977 kcal into carbohydrate and fat targets, take the figure into the macro split calculator.
Where inside the range to sit
Move towards the top of your band when three conditions apply: you are in a calorie deficit, you are training hard against resistance, and you are already lean. Each of those raises the value of dietary protein for preserving muscle, and all three together is the situation the highest published figures were derived from.
Move towards the bottom when you are eating at or above maintenance, training moderately, and have plenty of room in your calorie budget for carbohydrate to fuel that training. Extra protein beyond the point of diminishing returns is not harmful, but it displaces carbohydrate and fat that may be doing more for you.
Two practical constraints deserve mention. Protein is the most satiating macronutrient per calorie, which is genuinely helpful in a deficit and can be a problem in a surplus, where a very high protein target makes it hard to eat enough total energy. And protein is usually the most expensive part of the food bill, so a target you cannot afford to hit consistently is worse than a slightly lower one you can.
If you are using the lean mass basis, remember that the target inherits every error in the body fat estimate. A five-point error at 82 kg moves lean mass by 4.1 kg, which at 2.7 g/kg moves the target by 11 g — small enough not to matter much, which is reassuring. Estimate body fat with the Navy body fat calculator and do not agonise over the last percentage point.
Daily protein by goal and body weight
| Goal | g/kg | 60 kg | 80 kg | 100 kg |
|---|---|---|---|---|
| Sedentary (RDA) | 0.8–1.0 | 48–60 g | 64–80 g | 80–100 g |
| Older adult maintaining muscle | 1.0–1.2 | 60–72 g | 80–96 g | 100–120 g |
| Generally active | 1.2–1.4 | 72–84 g | 96–112 g | 120–140 g |
| Endurance training | 1.2–1.6 | 72–96 g | 96–128 g | 120–160 g |
| Resistance training | 1.6–2.2 | 96–132 g | 128–176 g | 160–220 g |
| Aggressive fat loss (per kg FFM) | 2.3–3.1 | 138–186 g | 184–248 g | 230–310 g |
The gap between the RDA and the resistance-training band is a factor of two to nearly three. That gap is the reason a single "recommended" protein figure is misleading.
Common errors in setting a protein target
- Setting protein as a percentage of calories. A fixed percentage cuts your protein every time you cut your calories. Set grams per kilogram and let the percentage fall where it falls.
- Applying a fat-free-mass factor to total body weight. The 2.3–3.1 g/kg range assumes lean mass. Applied to total weight at 30% body fat it overshoots by 43%.
- Counting protein from the raw weight of cooked food. Meat loses about a quarter of its weight in cooking, so 200 g raw is roughly 150 g cooked with the same protein content. Check which basis the label uses.
- Treating the top of the range as a minimum. Evidence for benefit above about 1.6 g/kg for muscle gain is inconsistent, and the extra calories have to come from somewhere.
- Ignoring distribution entirely. Reaching a daily total in one large meal produces a smaller synthetic response than spreading it across three or four.
- Assuming plant and animal sources are interchangeable gram for gram. Leucine content and digestibility differ, so a wholly plant-based diet usually needs a modestly higher total and more attention to combining sources.
Protein and kidney health
Intakes in the ranges on this page have not been shown to damage kidney function in people with healthy kidneys, and the claim that they do traces back to extrapolation from people who already had renal disease. The situation is genuinely different for anyone with existing kidney disease, where protein restriction may be part of treatment — in that case the target should come from a clinician, not a calculator.
Fitting protein into the rest of the diet
Protein is the macro to fix first, because its target is the best supported and because it is the one whose shortfall costs you most during a deficit. Once it is set in grams, everything else is easier: subtract its calories from your intake and split the remainder between carbohydrate and fat according to your training and preference.
The sequence that works is: estimate maintenance with the TDEE calculator; choose a deficit or surplus with the calorie deficit calculator; set protein here; then divide the remainder with the macro split calculator. Doing it in the other order — picking percentages first — tends to produce a protein figure that has no relationship to your body weight at all.
Two effects worth knowing about. Protein has the highest thermic effect of the three macronutrients, so a portion of the calories you eat as protein is spent digesting and processing it — a modest but real contribution to energy balance on a high-protein diet. And protein is the most satiating macronutrient per calorie, which is why high-protein diets tend to produce better adherence in a deficit even when calories are matched.
Finally, timing matters less than the internet suggests. The idea of a narrow post-workout anabolic window has not held up; what matters is the total daily amount, its distribution across several meals, and consistency across weeks. Getting the daily figure right and repeating it is worth far more than the timing of any single serving.