How much protein do you actually need? The evidence for desk workers

Protein is having a decade. It is added to everything from coffee to crisps, the daily protein target on social media keeps climbing, and “protein-maxxing” is a search term people actually type. Underneath the noise is a genuinely well-studied question with a reasonably clear answer, and a plateau that the marketing never mentions.

This guide separates the official minimum from the performance range, explains where the evidence for more protein stops, and works out what that means if your job is mostly sitting down.

Two different numbers, two different questions

The Recommended Dietary Allowance for protein exists to prevent deficiency. It was derived from nitrogen balance studies and set at 0.8 g per kg of body weight per day. One review describes its role precisely: the RDA is defined as the minimum amount of protein to prevent inadequacies in 97.5% of healthy adults. A minimum to avoid a problem is not the same as an optimum for building muscle.

The second number answers a different question: how much protein supports gains in muscle mass and strength when you train. The International Society of Sports Nutrition’s position stand puts that range at an overall daily protein intake in the range of 1.4-2.0 g protein/kg body weight/day for most exercising individuals.

Almost every argument online comes from conflating these two figures, or from quoting the higher one to people who are not doing the training that makes it relevant.

Where the muscle-building benefit plateaus

The most useful single study here is a meta-analysis and meta-regression that pooled data from 49 studies with 1863 participants on protein supplementation during resistance training. It found real but small average effects: added protein increased one-repetition-maximum strength by 2.49 kg and fat-free mass by 0.30 kg over the training periods studied.

Then it found the ceiling. Protein supplementation beyond total protein intakes of 1.62 g/kg/day resulted in no further gains in fat-free mass. In the same paper, the authors are equally direct about the low end, noting that consuming protein at the RDA of 0.8 g protein/kg/day appears insufficient for those who have the goal of gaining greater strength and fat-free mass with resistance training.

So the evidence supports a band rather than a target: below roughly 1.2 to 1.4 g/kg you are probably leaving results on the table if you lift; above roughly 1.6 g/kg the extra protein did not add muscle in these trials. That break point is an estimate rather than a hard cutoff, which is a reason to treat 1.6 as a reasonable planning number rather than a precise threshold.

Two moderators are worth knowing. The benefit of supplementation was reduced with increasing age, and it was more effective in people who were already resistance-trained.

What this means if you sit all day

Here is the arithmetic for an 80 kg desk worker.

At the RDA, 0.8 g/kg is 64 g a day. That is achievable without thinking about it: a couple of eggs, a chicken sandwich, some yoghurt.

At the plateau, 1.6 g/kg is 128 g a day. That takes deliberate planning: protein at every meal, and probably a shake.

The question is which number applies to you, and the honest answer depends almost entirely on whether you do resistance training. The plateau figure comes from trials of people lifting weights for six weeks or more. If you are not training, the studies that generated the higher number did not include anyone like you, and there is no trial showing that a sedentary person gains anything from doubling their protein.

None of this argues for the RDA as a goal either. Protein is filling, it supports muscle retention with age, and most people who eat a varied diet land somewhere between the two numbers anyway.

What the higher intakes do and do not do

The ISSN position stand notes higher protein intakes (2.3-3.1 g/kg/d) may be needed to maximize the retention of lean body mass in resistance-trained subjects during hypocaloric periods, which is to say during a deliberate fat-loss phase in already-trained people. That is a narrow case and not a general recommendation.

It also gives a per-meal figure worth knowing: general recommendations are 0.25 g of a high-quality protein per kg of body weight, or an absolute dose of 20-40 g. That is roughly a large chicken breast, a tin of tuna, or a standard scoop of whey.

Protein timing, the old “anabolic window”, has been steadily deflated by research. Total daily intake matters more than the clock.

What is not known

Long-term trials comparing protein intakes on hard health outcomes in healthy adults are scarce; most of the evidence is muscle and strength over weeks to months. Kidney concerns from higher protein in people with healthy kidneys have not been demonstrated in trials, but nor have decades of very high intake been studied. If you have kidney disease, protein intake is a clinical decision, not a fitness one.

This is not individual medical advice. Decisions about diet changes or supplements, particularly with any kidney or metabolic condition, belong with a clinician.

Common questions

How much protein per day do I need to build muscle?

Trial evidence supports roughly 1.4 to 2.0 g per kg of body weight for people doing resistance training, with a meta-regression finding no further fat-free mass gains beyond about 1.62 g/kg/day.

Is 0.8 g/kg of protein enough?

It is enough to prevent deficiency, which is what the RDA was designed for. The same meta-analysis noted the RDA appears insufficient for people whose goal is gaining strength and muscle through training.

How much protein can you absorb in one meal?

The ISSN’s per-serving recommendation is 0.25 g of high-quality protein per kg of body weight, or 20 to 40 g in absolute terms, for maximising muscle protein synthesis. That is a dose recommendation rather than an absorption limit.

Do I need extra protein if I do not exercise?

The evidence for higher intakes comes from resistance-training trials. No trial has shown that a sedentary adult gains anything from pushing protein towards 1.6 g/kg, so meeting or moderately exceeding the RDA is a defensible default.

The bottom line

If you lift, aim somewhere between about 1.4 and 1.6 g per kg and stop worrying past that, because the trials stop showing extra benefit there. If you do not lift, you are already close to where the evidence puts you, and the protein snack economy is selling you a number that was measured in someone else’s gym.