📉 Weight Loss · 11 min read · Subtopic 2 of 5

The 1.6–2.2 g/kg target in a cut

The range itself is easy to memorize: 1.6 to 2.2 grams of protein per kilogram of body weight per day. The interesting question is which end you belong at — and the answer, for almost anyone running a calorie deficit, is the top. This page walks the dose-response data that set the range, the deficit trials that justify pushing higher, and the plateau that tells you where to stop.

🔎 Evidence Snapshot ★★★★☆ Good — a large meta-analysis sets the dose-response, and several randomized trials in energy deficit confirm that higher protein preserves lean mass; the exact ceiling above ~2.2 g/kg is less well tested

What the evidence supports

  • The dose-response for muscle gain plateaus near 1.6 g/kg/day — protein above that adds little for training gains at maintenance.
  • In randomized deficits, protein at 1.6–2.4 g/kg/day measurably preserves lean mass where RDA-level diets lose it.
  • Leaner and older people, and anyone cutting fast or training heavy, have the strongest reason to sit at the top of the range.

What remains uncertain

  • Whether protein beyond roughly 2.2 g/kg adds further protection — the tested doses suggest a flat or very shallow curve.
  • Exactly where the optimum sits for individual body types and training volumes; the range is a band, not a point.
  • How the bodyweight denominator should be chosen for very overweight people — current, goal, or adjusted weight.

Evidence last reviewed: August 15, 2026. Conclusions may change as new research is published.

the top of the range

Where the Range Comes From

The 1.6 number is not folklore. A large systematic review and meta-regression of 49 randomized trials with 1,863 participants modeled how protein intake maps onto resistance-training gains and found that the curve bends — beyond roughly 1.62 g/kg/day (95% confidence interval 1.03 to 2.20), additional protein produced little additional muscle (Morton et al., British Journal of Sports Medicine, 2018). That analysis describes people trying to add muscle at maintenance energy. It is the load-bearing reference for the lower end of the cut range: 1.6 g/kg is the dose at which the body has essentially everything it can use for building. The range's upper end, 2.2, is a defense allowance added for the specific conditions of a deficit.

It is worth being precise about what the meta-analysis does and does not show. It shows a plateau for muscle gain, which is not the same claim as a plateau for muscle preservation during weight loss. Preservation is the harder task — the body is being asked to hold tissue it is actively instructed to shed — and that difference is why the cut range sits higher than the maintenance number.

Two practical notes on the numbers. First, the meta-analysis's confidence interval is wide — 1.03 to 2.20 g/kg — the statistical way of saying that some people need less and some need more, and the band is a working range, not a courtroom verdict. Second, the range is calculated per kilogram of total body weight, which is why the arithmetic table below matters more than the abstract figure: the same 2.0 g/kg is a very different plate of food at 60 kg than at 100 kg.

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Why a Deficit Pushes You Up the Range

Think of protein as a substrate budget. At maintenance the budget pays for repairs. In a deficit it must also pay the cost of resisting the catabolic signal described on the first page of this series — and the trials say the higher budget works. A 21-day 40% deficit trial tested protein at 0.8, 1.6, and 2.4 g/kg/day and found the RDA-level group lost significantly more fat-free mass than both higher groups, while 1.6 and 2.4 behaved similarly (Pasiakos et al., 2013). In athletes on a short aggressive cut, 2.3 g/kg preserved lean mass where 1.0 g/kg lost it (Mettler et al., 2010). And with training added, 2.4 g/kg allowed overweight young men to gain lean mass even while losing fat (Longland et al., 2016). The pattern across all three: once you are at or above ~1.6–2.2 in a deficit, you have bought the protection; below it, you are losing tissue you did not need to lose.

The Doses Tested in the Deficit Trials
g/kg/day of protein; bar lengths are proportional to the dose itself, which is real and published. The higher doses (1.6–2.4) preserved lean mass or allowed gains in deficit RCTs; the RDA-level diet lost it (Pasiakos et al., 2013; Mettler et al., 2010; Longland et al., 2016).
2.4 g/kg — top tested gained lean mass with training 2.2 g/kg — top of range preserved lean mass 1.6 g/kg — bottom of range largely preserved 0.8 g/kg — US RDA lost lean mass

The Arithmetic for Your Bodyweight

Once the target is set, the rest is multiplication. The range maps onto body weight as follows — the floor protects against the worst case, the top buys the full defense. Most people cutting should land in the upper half.

Body weight1.6 g/kg floor2.2 g/kg topWhere you likely sitRead
🥉 60 kg 96 g 132 g Upper half if lean or training 110–130 g
⚖️ 70 kg 112 g 154 g Upper half if lean or training 125–155 g
🥩 80 kg 128 g 176 g Typical male cut — aim high 145–175 g
🏋️ 90 kg 144 g 198 g Closer to goal — sit near the top 165–195 g
🧱 100 kg 160 g 220 g Heavy cutters — top half protects muscle 180–220 g

The denominator question deserves an honest answer: use the body weight you are currently defending — not your goal weight, and not a dream weight from a decade ago. For people carrying a very large fat reserve, some practitioners use an adjusted weight, because fat needs little protein to maintain; the honest move is to compute on current weight and treat the top of the range (closer to 2.2 g/kg on leaner frames) as the safe direction when unsure.

When to Sit at the Top

The range is a tool with a clear instruction: in a cut, drift up. The decision rules are concrete.

🥩 The number above 2.2 is not a commission

The honest reading of the data is a plateau, not a ceiling that grows with effort. In Pasiakos's trial, 2.4 g/kg did not protect meaningfully more than 1.6. The extra grams cost calories you might rather spend on food you enjoy — and on a cut, food you enjoy is a retention tool. Treat 2.2 as a stopping point for almost everyone, and spend your remaining effort on the spacing and the training that the next pages cover.

~1.62
g/kg/day — the meta-analytic breakpoint where gain per gram flattens (Morton et al., 2018)
1.6–2.2
g/kg/day — the cut range; deficits move you toward the top
176 g
at 80 kg × 2.2 — roughly four doses of ~40 g each across the day

Questions, Answered Briefly

The Bottom Line

  1. The range sits on a real dose-response curve — plateaus near ~1.6 g/kg/day for gains, so the cut range extends higher for the harder job of preservation.
  2. Deficit trials put you at the top — 1.6–2.4 g/kg preserved lean mass where RDA-level intake lost it, across three randomized studies.
  3. Compute on current weight and drift up — leaner, older, faster-cutting, and plant-based eaters sit at the top; the top beats the floor when unsure.
  4. Respect the plateau — beyond ~2.2 g/kg the protection flattens; spend the remaining effort on spacing and training, not more grams.

Related Topics

Sources & further reading