How Much Protein Per Day? The Numbers That Actually Have Evidence

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
Active adults (appetite, body composition)	1.2–1.6	0.55–0.7	Above-RDA intakes studied for appetite and body-weight management
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	1.0–1.2 (1.2+ if active)	0.45–0.55 (0.55+)	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 trials of healthy adults, higher protein intakes did not change kidney function. The 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 (full rankings: highest protein per 100 g and highest protein per calorie):

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	~9 g
Canned tuna	1 tin, drained	~20 g

An 80 kg person targeting 1.8 g/kg needs 144 g (the macro calculator works out a target from your own weight). A yogurt at breakfast, a tin of tuna at lunch, a whole chicken breast at dinner and a shake come to about 115 g; two eggs and a cup of lentils close the gap.

Sources

Wolfe RR, Cifelli AM, Kostas G, Kim IY. (2017). Optimizing protein intake in adults: interpretation and application of the Recommended Dietary Allowance compared with the Acceptable Macronutrient Distribution Range. Advances in Nutrition 8(2):266–275. doi:10.3945/an.116.013821
Morton RW, Murphy KT, McKellar SR, et al. (2018). A systematic review, meta-analysis and meta-regression of the effect of protein supplementation on resistance training-induced gains in muscle mass and strength in healthy adults. British Journal of Sports Medicine 52(6):376–384. doi:10.1136/bjsports-2017-097608
Jäger R, Kerksick CM, Campbell BI, et al. (2017). International Society of Sports Nutrition Position Stand: protein and exercise. Journal of the International Society of Sports Nutrition 14:20. doi:10.1186/s12970-017-0177-8
Longland TM, Oikawa SY, Mitchell CJ, et al. (2016). Higher compared with lower dietary protein during an energy deficit combined with intense exercise promotes greater lean mass gain and fat mass loss: a randomized trial. American Journal of Clinical Nutrition 103(3):738–746. doi:10.3945/ajcn.115.119339
Bauer J, Biolo G, Cederholm T, et al. (2013). Evidence-based recommendations for optimal dietary protein intake in older people: a position paper from the PROT-AGE Study Group. Journal of the American Medical Directors Association 14(8):542–559. doi:10.1016/j.jamda.2013.05.021
Devries MC, Sithamparapillai A, Brimble KS, et al. (2018). Changes in kidney function do not differ between healthy adults consuming higher- compared with lower- or normal-protein diets: a systematic review and meta-analysis. Journal of Nutrition 148(11):1760–1775. doi:10.1093/jn/nxy197
Leidy HJ, Clifton PM, Astrup A, et al. (2015). The role of protein in weight loss and maintenance. American Journal of Clinical Nutrition 101(6):1320S–1329S. doi:10.3945/ajcn.114.084038
Phillips SM, Tipton KD, Aarsland A, et al. (1997). Mixed muscle protein synthesis and breakdown after resistance exercise in humans. American Journal of Physiology 273(1):E99–E107. doi:10.1152/ajpendo.1997.273.1.E99

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 about 2.2 g/kg, meta-analyses find no further gain in lean mass, and the calories displace carbs and fat you may want for training. In trials of healthy adults, higher protein intakes did not change kidney function.

How much protein per day to lose weight? Toward the top of the range, 2.0–2.4 g/kg while training. Higher-protein meals also modestly increase fullness, which can make the deficit easier to hold.

Do I need protein on rest days? Yes. Muscle protein synthesis stays elevated 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 (compare firm tofu vs chicken breast), 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.