How Much Protein Per Day? The Numbers That Actually Have Evidence
The RDA is 0.8 g/kg. Research on people who lift says 1.6–2.2 g/kg. Here's where each number comes from, and how to pick yours.
For most active adults, 1.6–2.2 grams of protein per kilogram of bodyweight per day (roughly 0.7–1.0 g per pound) covers the evidence-supported range. The official RDA of 0.8 g/kg is not a target for athletes — it’s the minimum that prevents deficiency in a sedentary population, and studies of resistance-trained people consistently show benefits well above it. If you’re cutting, aim at the top of the range; muscle preservation in a deficit is where protein does its most visible work.
The numbers, by situation
| Situation | Grams per kg bodyweight | Grams per lb | What it’s based on |
|---|---|---|---|
| Sedentary adult, deficiency floor | 0.8 | 0.36 | The RDA — a minimum, not an optimum |
| General health, active lifestyle | 1.2–1.6 | 0.55–0.7 | Above-RDA intakes for body composition and satiety |
| Building muscle | 1.6–2.2 | 0.7–1.0 | Resistance-training meta-analyses; gains plateau near the bottom of this range |
| Cutting while lifting | 2.0–2.4 | 0.9–1.1 | Higher intakes preserve lean mass under an energy deficit |
| Adults over 65 | 1.0–1.6 | 0.45–0.7 | Older muscle responds less to a given protein dose |
Use bodyweight if you’re at a reasonable body fat percentage. If you’re carrying substantial excess fat, these numbers scale better against a goal weight or lean mass — fat tissue has no protein requirement, and scaling off total bodyweight at high body fat produces targets that are needlessly hard to eat.
Why the RDA is the wrong number for lifters
The 0.8 g/kg RDA answers a specific question: how little protein can a healthy sedentary adult eat without going into nitrogen deficit? That’s a floor for avoiding harm, not a ceiling for pursuing benefit — and the population studied was not training.
Meta-analyses of resistance-trained people find gains in lean mass continue past the RDA and flatten out around 1.6 g/kg, with confidence intervals extending toward 2.2. That flattening is why the practical advice lands at 1.6–2.2: below it you’re leaving results on the table, above it you’re mostly spending appetite for very little return.
Does timing matter?
Less than the internet suggests, but not zero:
- Daily total is the dominant variable. Hitting your number matters far more than when you hit it.
- Spreading across 3–5 meals of 25–40 g each is a reasonable default — enough per meal to maximally stimulate muscle protein synthesis, without pushing everything into one sitting.
- The “anabolic window” is wide. The idea that protein must arrive within 30 minutes of training does not hold up; the window is measured in hours.
- Pre-sleep protein has modest support for overnight recovery, but it’s an optimisation, not a requirement.
If you’re spreading protein across meals, this is precisely the kind of thing a log makes visible — you’ll often find the whole day’s protein is stacked into dinner.
Is high protein bad for your kidneys?
In people with healthy kidneys, no. That concern comes from advice given to patients with existing kidney disease, where protein restriction is genuinely part of treatment, and it was generalised to the healthy population where the evidence does not support it. If you have kidney disease or any renal risk factor, this is a question for your doctor, not an article.
Making the number practical
Grams per kilogram is abstract until you see it in food. Rough protein content of common sources:
| Food | Serving | Protein |
|---|---|---|
| Chicken breast | 100 g cooked | ~31 g |
| Greek yogurt, 0% | 170 g cup | ~17 g |
| Eggs | 2 large | ~12 g |
| Lentils, cooked | 1 cup | ~18 g |
| Whey protein | 1 scoop | ~24 g |
| Tofu, firm | 100 g | ~17 g |
| Canned tuna | 1 tin, drained | ~25 g |
An 80 kg person targeting 1.8 g/kg needs 144 g — reachable with a yogurt at breakfast, a tin of tuna at lunch, a chicken breast at dinner, and a shake, with room left over.
Frequently asked questions
How much protein do I need to build muscle? 1.6–2.2 g per kg of bodyweight per day, alongside resistance training. Protein without the training stimulus doesn’t build muscle; training without adequate protein limits what the stimulus can produce.
Can I eat too much protein? Above roughly 2.5 g/kg there’s no evidence of added benefit for muscle, and the calories displace carbs and fat you may want for training and hormones. It isn’t dangerous for healthy people — it’s just no longer useful.
How much protein per day to lose weight? Toward the top of the range, 2.0–2.4 g/kg while training. Protein is also the most satiating macro per calorie, which makes the deficit itself easier to hold.
Do I need protein on rest days? Yes. Muscle repair runs for 24–48 hours after a session, and your daily target shouldn’t move with the training calendar.
Is plant protein worse? Per gram, plant sources are generally lower in leucine and less complete in amino acid profile, so plant-based eaters do well at the higher end of the range and by varying sources. The total still dominates.
Next: what macro split to use when cutting, or how to count macros if you haven’t set targets yet.