For body composition change, the right protein target is 1.6 to 2.2 grams per kilogram of lean body mass per day. Lean body mass, not total body weight. A 100 kg person at 30 percent body fat carries 70 kg of lean mass, which sets the target at roughly 112 to 154 grams of protein per day, not the 160 to 220 grams a body-weight calculation would imply. This range is where the research consistently shows muscle is preserved during fat loss, muscle is built during a controlled surplus, and satiety holds well enough that the rest of the diet stays manageable. Below this range you are leaving body composition outcome on the table. Above it, returns diminish quickly. This article explains why, how to distribute the intake, and the caveats that actually matter.

Why lean body mass is the right denominator

The 0.8 grams per kilogram of bodyweight figure that anchors most mainstream nutrition advice was derived to prevent deficiency in sedentary populations. It is the floor below which problems start to appear, not the target above which body composition starts to change. Treating the deficiency floor as a body composition prescription is the central confusion in most generic protein advice.

Bodyweight as a denominator also distorts the target. A 100 kg person at 30 per cent body fat carries 70 kg of lean tissue. A 100 kg person at 15 per cent body fat carries 85 kg. The metabolic demand sits with the lean tissue, not the fat mass. Calculating from bodyweight overshoots for the higher-body-fat person and undershoots the leaner one. The numbers feel close on paper. The downstream results are not.

Lean body mass is the metabolically active tissue. Muscle, organs, bone-supporting tissue, the systems that actually consume amino acids to maintain themselves. Setting protein from that figure produces a target that fits the biology rather than the bathroom scale.

The 1.6 to 2.2 range, unpacked

The 1.6 to 2.2 grams per kilogram of lean body mass range comes out of multiple meta-analyses on resistance training, protein intake, and body composition outcomes. Below 1.6 g/kg lean mass, the lean-mass preservation and growth response is consistently submaximal. Above 2.2 g/kg lean mass, additional protein produces diminishing returns without obvious downside but without obvious gain either.

Where you sit inside the range depends on your goal.

  • Fat loss sits at the higher end (1.9 to 2.2 g/kg lean mass). Calorie deficit increases the demand on the protein system to defend lean tissue. Protein also drives satiety, which is the friction that most cuts come unstuck on.
  • Recomposition (losing fat while gaining muscle, possible for beginners and returners) sits in the middle (1.7 to 2.0 g/kg lean mass).
  • Maintenance and the muscle-gain phases of structured training sit at the lower end (1.6 to 1.8 g/kg lean mass), with calorie surplus doing more of the work.

The window is small enough that the difference between hitting it and missing it is real. A person undershooting the range by 30 grams a day for a year is leaving a meaningful body composition outcome on the table.

Distribution across meals: the leucine threshold

Muscle protein synthesis (the rebuilding process you are feeding) is triggered by leucine, the most anabolic of the essential amino acids. The threshold for maximally stimulating that response in a single meal sits at roughly 2.5 to 3 grams of leucine, which translates to 30 to 40 grams of complete protein per meal in most people.

Three to five eating occasions across the day, each hitting the threshold, give you several activations of muscle protein synthesis spread across the day. One enormous protein meal followed by lighter meals technically delivers the daily total but only triggers the anabolic response once. The total matters. The distribution matters nearly as much.

The practical pattern is three primary meals at 30 to 40 grams of protein each, with one or two supplementary protein-anchored snacks if the daily total needs more room. People who hit a high daily total through one steak dinner are leaving the response on the table that the same protein, distributed, would have triggered.

Anabolic resistance: why this matters more after 40

Anabolic resistance is the age-related reduction in muscle protein synthesis response to a given dose of protein. Put plainly, older adults need more protein per meal to produce the same anabolic response that a smaller dose produced in their twenties.

The practical implication: the 30 g floor per meal becomes 40 g for most adults over 40. Daily total stays in the 1.6 to 2.2 g/kg lean mass range. The per-meal dose climbs.

This is one of the most consistent gaps we see in clients over 40. Their daily total is reasonable on paper. Distribution is fine on paper. They still are not getting the body composition response their training and diet should produce. Pushing per-meal dose to the higher floor often resolves it without any other change. For more on the broader nutrition shift required after 40, see how to eat after 40.

Protein quality and bioavailability

Not all protein scores the same. DIAAS (Digestible Indispensable Amino Acid Score) is the current standard for measuring how well a protein source delivers usable amino acids in the proportions humans need.

At the top: whey, milk, eggs, fish, beef, lamb, chicken, pork. These are complete proteins with high digestibility and balanced amino acid profiles. Per gram, they do the most structural work.

In the middle: soy, mycoprotein (Quorn), some pea isolates. Complete or near-complete, with somewhat lower DIAAS scores than animal sources but still effective at sensible portions.

Lower: most single plant sources (rice, wheat, beans, nuts) score lower individually because they are missing or low in one or more essential amino acids. Combining sources (rice and beans, hummus and pita) improves the profile. Total volume needs to be higher to hit the same usable protein dose.

The practical reading: animal sources do more work per gram and per meal, particularly for the leucine threshold. Plant-based eating works for body composition when designed deliberately around higher volume, strategic combination, and selective use of higher-DIAAS plant proteins like soy. It does not work by accident.

For the broader frame on protein need across goals, see how much protein do I actually need.

Practical NZ protein sources

Local options that pull weight per dollar and per gram:

  • Grass-fed beef and lamb. NZ produces some of the world's best. Mince, steak, slow-cooked cuts. Roughly 25 to 30 g protein per 100 g cooked.
  • Wild-caught fish from NZ waters: hoki, blue cod, snapper, gurnard, salmon (farmed), terakihi. Roughly 20 to 25 g protein per 100 g cooked. Salmon brings omega-3s as well.
  • Free-range or pasture-raised eggs. Around 6 to 7 g protein per egg. Cheap, complete, fast.
  • Dairy: Greek yoghurt (15 to 20 g per 200 g serve), cottage cheese (12 g per 100 g), milk (3.4 g per 100 ml). Useful for hitting per- meal targets without bulk.
  • Chicken breast and thigh from NZ producers. Around 25 to 30 g per 100 g cooked.
  • Whey protein supplements where whole foods are not getting you to the daily total. Around 20 to 25 g per scoop with most reputable brands.
  • Plant options: tofu, tempeh, edamame, lentils. Useful for meal variety. Need volume to hit per-meal targets.

Rough cost ballpark in NZ at current prices (as of May 2026): eggs and milk are the cheapest cost-per-gram complete protein. Whey supplements are competitive at bulk pricing. Grass-fed red meat varies by cut. Wild fish is expensive per gram but brings the omega-3 benefit.

When supplementing is sensible

Whole foods first because they bring fibre, micronutrients, and satiety the powders do not. Supplement when whole foods are not getting you there.

The cases where a whey or casein scoop earns its place:

  • Daily target is high (110 g+) and three meals do not have the appetite to deliver it.
  • Time-constrained mornings or post-training windows where a real meal is not happening.
  • Travel or shift work breaking the normal meal pattern.
  • Older adults pushing per-meal dose to 40 g and finding food alone is not getting there.
  • GLP-1 users with reduced appetite where the priority is defending lean mass with limited food volume.

Whey is the workhorse for most uses (fast-digesting, high leucine). Casein has its place at night or as a slow-release option. Plant-based blends (pea + rice) work for those avoiding dairy. Collagen does not substitute for these. See does collagen protein actually work for what collagen is and is not useful for.

How body composition scanning sets the right target

Without a body composition scan, you are guessing at your lean body mass. Bodyweight, height, age, and sex give you an estimate. Estimates miss by enough that the protein target lands either materially low or materially high.

A BIA scan delivers the lean mass figure directly, segmental data on where that lean mass sits, and a body fat percentage you can trust to within reasonable margin. Re-scanning monthly gives you the trend that shows whether the protein target is actually defending what it is supposed to defend.

The scan is the foundation. Set the protein number on real data. Adjust on what the next scan shows. The body composition scanning guide covers what scans actually measure and how to read them.

Common mistakes

The repeating patterns we see in clients arriving with stalled results:

  • Underestimating intake by 20 to 40 grams a day. People remember the steak dinner and forget the bread, the snacks, the lower-protein lunch. Track for two weeks honestly and the gap usually shows.
  • Calculating from bodyweight rather than lean mass and ending up either over-targeted (frustrating, expensive, satiety blown) or under-targeted (failing to defend lean tissue).
  • Front-loading protein in one meal. The daily total is fine. The per-meal dose pattern is wrong. Spread the load.
  • Counting collagen, gelatin, or low-DIAAS plant sources toward the total at face value. They are not equivalent currency. Count complete protein sources at full value, supplement plant sources toward higher volume, treat collagen as a separate tool.
  • Hitting the target on average across the week but missing on most days. Big weekends do not rescue thin weekdays. The body responds to the daily input.

How Inception Nutrition prescribes protein

Every coaching client gets a protein target set from their body composition scan, distributed across the meal pattern that fits their life, and tracked against actual intake rather than estimated intake. The Coaching programmes build the rest of the diet around the protein floor. The Free Metabolic Audit is the starting point if you want a baseline read first.

For a deeper read on protein and metabolic health more broadly, see the complete guide to metabolic health for New Zealanders.