How Much Protein Do You Actually Need?

The honest answer is this: 1.6 g/kg is the original consensus ceiling, and 2.2 g/kg or higher is where newer reanalysis is pointing. Neither number is silly, and neither side has to be treated as wrong, because they are evidence-based answers produced by different cuts of the data.

The better question is where inside that range your body size, diet phase, training, appetite, digestion, budget, and adherence put you.

Where 1.6 g/kg Came From

The 1.6 g/kg figure comes from Morton and colleagues' 2018 meta-analysis in the British Journal of Sports Medicine (Morton et al., 2018, BJSM). It pooled randomised controlled trials of protein supplementation alongside resistance training, then modelled the dose-response relationship between protein intake and fat-free mass gain.

The headline result was that gains appeared to plateau at roughly 1.6 g/kg/day, with an upper confidence interval around 2.2 g/kg/day (Morton et al., 2018, BJSM). Over time, "1.6 is enough" became "anything above 1.6 is pointless".

That is not quite what the paper can prove. It was mostly a hypertrophy question in people doing resistance training, not a cutting-specific muscle-preservation question. The available trials varied by training status, baseline protein, energy balance, age, and study design.

So 1.6 g/kg is not a bad number. For many lifters eating at maintenance or in a small deficit, it is a defensible floor. It just should not be treated as a hard biological ceiling.

Where 2.2 g/kg and Higher Is Coming From

The renewed push toward 2.2 g/kg and above is largely driven by Greg Nuckols' 2024 Stronger By Science reanalysis of the Morton data (Nuckols 2024, Stronger By Science). The key point was not "Morton was wrong". It was that the plateau in the original model was poorly identified.

Nuckols' reanalysis argued that the confidence interval around the protein ceiling extended well beyond the quoted central estimate, with point estimates still compatible with further hypertrophy at intakes of 2.2 g/kg or more (Nuckols 2024, Stronger By Science). That does not mean everyone needs 2.6 g/kg. It means higher intakes remain evidence-compatible.

Tagawa and colleagues add context. Their 2020 meta-analysis in Nutrition Reviews examined protein intake and fat-free mass across a wider range of intervention studies and reported a dose-response pattern that did not neatly stop at 1.6 g/kg (Tagawa et al., 2020, Nutrition Reviews).

The sensible reading is: 1.6 g/kg is a credible lower anchor, 2.2 g/kg is a credible upper everyday target, and 2.4-2.6 g/kg can be justified in harder cuts or leaner trainees.

Why One Number Is the Wrong Frame

Protein targets are usually given per kilogram of bodyweight, but "bodyweight" is doing a lot of work. An 80kg lean lifter and an 80kg beginner with much higher body fat do not have the same lean tissue requirement. Lean mass is cleaner if you know it. Total bodyweight is fine if you do not.

Training status matters too. Novices can grow on less precise nutrition because the training stimulus is new. Advanced lifters have less room for error, especially when lean and dieting.

Deficit depth changes the trade-off. A mild 300 kcal deficit is not the same problem as a rapid cut where hunger, recovery, and training performance are all under pressure. Older lifters may also benefit from aiming higher because muscle protein synthesis becomes less responsive with age.

Then there is normal life. Higher protein can improve satiety, but it can also be expensive, repetitive, and hard on digestion. Vegan diets can hit high targets, but often need more planning.

How to Pick Your Target

Use this as a practical decision tree, then plug the result into your full calorie setup in the macro calculator guide.

If you are cutting hard: aim for 2.2-2.6 g/kg total bodyweight, or use the higher end of your lean-mass estimate. This is most relevant when calories are low and body fat is already moderate to low.

If you are a novice or returning lifter: aim for 1.6-2.0 g/kg. You are likely to respond well to training itself, so consistency and total calories matter more than forcing a maximal protein target.

If you are older, very lean, or highly trained: aim for 2.0-2.4 g/kg. The extra buffer is reasonable because the cost of muscle loss is higher.

If you follow a vegan diet: aim for 1.8-2.4 g/kg, biased upward if most of your protein comes from lower-leucine foods.

If hunger is your main problem: aim for 2.0-2.4 g/kg if it helps you stay full. Lean meat, fish, eggs, Greek yoghurt, tofu, tempeh, seitan, and protein powder can make a deficit easier.

If cost or digestion is the limiting factor: aim for 1.6-2.0 g/kg and stop apologising for it. Hitting that range daily is better than writing 2.4 g/kg into a spreadsheet and missing it four days a week.

Maintenance Is Different From Cutting

During a maintenance phase, you usually have more calories, better recovery, and less hunger. That means you can often sit closer to 1.6-2.2 g/kg. If you have just finished a long cut, are lean, or are trying to consolidate strength, biasing toward 2.0-2.2 g/kg is sensible.

During a cut, the argument for the higher end gets stronger because protein helps with both lean-mass retention and hunger management.

The Boring Truth

The boring truthful conclusion is that hitting 1.6 g/kg with consistency beats missing 2.2 g/kg because it only worked in theory. If 1.6 g/kg is the highest target you can hit every day while training hard and staying in your deficit, use it. If 2.0-2.4 g/kg makes the diet easier and fits your calories, use that.

The evidence does not demand one winner. It gives you a range. Your job is to choose the part of that range you can repeat.

Sources

1. Morton RW et al. (2018). Protein supplementation, resistance training, muscle mass, and strength. British Journal of Sports Medicine.
2. Nuckols G (2024). Protein Science Updated. Stronger By Science.
3. Tagawa R et al. (2020). Dose-response relationship between protein intake and muscle mass. Nutrition Reviews.