Metabolic Natures — Two Axes, Six Positions, A Place to Start

The Core Question

Why does every diet work
for someone — but not for everyone?

For decades, the nutrition conversation has been dominated by competing dietary ideologies — low fat, low carb, paleo, ketogenic, carnivore, plant-based. Each has its passionate advocates. Each has its disillusioned failures. And each keeps generating the same pattern: it works brilliantly for some people and makes others feel significantly worse.

This is not a paradox. It is a predictable consequence of applying population-level dietary advice to individuals whose metabolisms operate on fundamentally different principles. The person who does well on less starch and more fat is not the same metabolic system as the person who does well on more starch. The difference is not willpower. Part of it is that people respond very differently to the same meal, which is well evidenced; part of it is whether a plan fits the life it has to run in, which is what the long-term trials keep finding matters most.

Metabolic Natures is a framework for deciding where to start. A structured questionnaire captures the pattern you recognise in yourself — how you have always run, not how you have been for the last fortnight. Functional testing describes what your biochemistry is doing now. The two frequently disagree, and the disagreement is the clinically useful part: it identifies what is currently in the way. Guidance follows the current constraint until the constraint resolves. Built on three decades of practice, and stated with its limits attached rather than without them.

"The question was never which diet is correct. It was which system it was landing on, what is currently in the way, and whether we wrote down beforehand what we expected to change."

What this is, and what the evidence for it actually is

Metabolic Natures is a framework for deciding where to start, not a test result.

What is well supported: people respond very differently to the same meal. One study tracked 800 people across nearly 47,000 meals and found high variability in blood glucose after identical meals DOI; another, of 1,002 UK adults, found the same for glucose, insulin and blood fats — several of its authors work for a commercial nutrition company, which we note as we would for any study DOI.

What is not established: that any one person does better long-term on one particular balance of food. When four named diets were compared for a year, weight loss tracked how well people stuck to the plan (r = 0.60) and essentially not at all which plan it was (r = 0.07, not significant). DOI The balance you can actually sustain is the one that works.

The specific categories are not validated by controlled trials, and we do not claim they are. No trial has tested whether assigning someone to an oxidative or autonomic category, and matching a macronutrient ratio to it, produces a better result. The closest test of that shape of argument is DIETFITS — 609 adults, healthy low-fat against healthy low-carbohydrate, twelve months, a difference of 0.7 kg between arms, and neither a genotype pattern nor baseline insulin secretion predicted which diet suited whom. DOI DIETFITS did not test oxidation rate or autonomic tone, so it is not a direct refutation — but it tested the logic, and the logic did not hold up.

So what are we claiming? That a structured way of recognising your own long-standing pattern, adjusted from what your test findings currently show, gives you an approach you can recognise yourself in and therefore sustain. And one thing more, which is the part that can be wrong: we write down, before your protocol starts, what we expect to change and by when — and we check it at retest. That prediction can come back not met. Nothing else in the framework can.

And what we are not selling. Metabolic Natures recommends no proprietary formula, and no product is required for the method to work. The lineage this framework comes from did the opposite — it defined its own efficacy as depending on a sole-source supplement range. That is named here because the same standard has to apply to a tradition we came from as to one we did not.

Read the corrections to the book, dated →

Two axes, three positions on each

Metabolic Nature is described on two axes. You are given a position on each, with its strength, rather than a single label — so how close to the middle you sit is visible instead of hidden. The axes come from clinical observation, not from a validated measurement, and that is stated below rather than glossed.

Autonomic Nervous System Dominance

The balance between sympathetic (activating) and parasympathetic (restorative) tone. Shapes how the body responds to stress, how nutrients are mobilised, and how the digestive system functions. This axis adjusts the carbohydrate share within the food framework; it never sets the framework on its own. Current autonomic and adrenal output is described by the cortisol diurnal curve on DUTCH. No blood marker has been shown to identify an autonomic type, and none is used here as though it did.

Cellular Oxidation Rate

The speed at which cells convert nutrients to energy. The framework’s working assumption, from clinical observation rather than trials, is that the fast end tends to do better with less starch and more fat, and the slow end with more starch. This is the axis that sets the starting balance of starch and fat, and it is read from the questionnaire. Protein is not on this axis: it is set by your body weight and is the same on every plate. Organic acids describe how mitochondrial energy production is currently running; that is a useful and different question, and it is not a measurement of oxidative type.

The Six Metabolic Natures

Six positions across two axes —
you are given one from each.

Each card says how a position is recognised on the questionnaire. That is how it is scored, so it is not evidence about the position.

CA · Oxidative

Catalyst

Oxidative axis — fast end

The fast end of the axis that sets the food framework. Hunger comes early and strongly, and starch-led meals tend not to hold. The starting plate has less starch and more fat — carbohydrate 20–30% of energy, with fat mostly from olive oil, oily fish, nuts and seeds — and how far toward that end depends on how strong the reading is. What testing shows now can override it. Protein is set by body weight, not by this reading.

How it is recognised

Hungry again soon after a starch-led meal
Strong appetite; larger portions than most
Steadier after a protein-rich meal with some fat
Wants something substantial early in the day

AD · Oxidative

Adaptive

Oxidative axis — middle

The middle of the oxidative axis. Mixed meals land well and neither end pulls strongly, so the starting plate is balanced — carbohydrate 30–50% of energy. It is also the plate for any reading too weak to name an end. A smaller group reads strongly toward both ends at once; for them, alternating the two frameworks in blocks can be tried as a recorded experiment, led by the practitioner.

How it is recognised

Most ordinary meals land fine
No strong pull toward rich or starchy food
Appetite about average

EN · Oxidative

Endurance

Oxidative axis — slow end

The slow end of the oxidative axis. Appetite is lighter, starch-led meals sit well and rich, fatty meals feel heavy. The starting plate has more starch and less fat — carbohydrate 50–60% of energy, with fat never below about a fifth — adjusted in the same way.

How it is recognised

Light and clear-headed after a starch-led meal
Heavy or sluggish after a rich, fatty meal
Little appetite first thing
Smaller portions than most

NK · Autonomic

Kinetic

Autonomic axis — sympathetic end

Quick to mobilise and slow to stand down. This reading does not set the food framework: it moves the carbohydrate share up a little — about two tablespoons of cooked rice a meal, and only when the reading is strong (50% or more) — within whichever plate the oxidative reading sets. That direction is a current position, not a finding. Meal timing follows your own answers, not the label.

How it is recognised

Slow to fall asleep, mind still active
Wakes in the night and struggles to settle
Runs warm
Startles easily
Keyed up and sharp under sustained pressure

CB · Autonomic

Calibrated

Autonomic axis — middle

Settles and responds without a strong pull either way. No adjustment to the food framework.

How it is recognised

Falls asleep and stays asleep without much trouble
Neither runs hot nor feels the cold first
Pressure registers, then passes

GR · Autonomic

Grounded

Autonomic axis — parasympathetic end

Settles easily and is slow to be roused. Moves the carbohydrate share down a little — about two tablespoons of cooked rice a meal, and only when the reading is strong (50% or more) — an interim position, stated as one. Meal timing follows your own answers.

How it is recognised

Asleep quickly and sleeps through
Feels the cold before others
Slow to startle
Withdraws and wants more sleep under pressure

How to read these six. Catalyst, Adaptive and Endurance are positions on the oxidative axis. Kinetic, Calibrated and Grounded are positions on the autonomic axis. You are not one of six types. You get a direction and a strength on each axis, in fixed order — oxidative first, autonomic second. A result reads like oxidative: fast, lean 72%, strength 64% · autonomic: parasympathetic, lean 68%, strength 41% — low strength, not “you are a Catalyst”. The oxidative reading sets the food framework; the autonomic reading adjusts carbohydrate within it and never sets it. The cut-offs — 60% to name a direction, under 50% strength counted as low, fewer than 70% of questions answered counted as provisional — are judgement, not evidence, and are stated as such.

And on test signatures. Earlier versions of this page listed a set of blood markers under each type as its laboratory signature. Those have been removed. No published validation has been found that the calcium-to-phosphorus ratio, the eosinophil-to-basophil ratio, or any Krebs-cycle pattern predicts which balance of food suits a person. The panels describe how your system is running now — which is genuinely useful, and is a different claim.

What the Testing Adds

What the panels can tell you —
and what they cannot

The questionnaire has a real limitation and it is worth stating plainly. Self-report is contaminated by current state: someone fifteen years into a diet that does not suit them has adapted, imperfectly, and answers from inside that adaptation. It is a starting hypothesis, not a finding.

The tests have the opposite limitation. They are objective and repeatable, and they are unambiguously a snapshot of the present. Bicarbonate, triglycerides, total protein and the rest move with recent diet, hydration, illness and training load. A panel taken today reports today. That is exactly what makes them useful — they show what is currently in the way — and it is also why they are not a window onto anything constitutional.

Under sustained HPA activation both instruments are pushed in the same direction at once, so there is no clean reading available from either side. When that is the case, the honest position is that the starting point is provisional until the constraint clears, and you will be told so.

What Each Panel Describes About Current Function

Blood Chemistry

The Metabolic Foundation

Total protein and albumin describe current protein status and catabolic load. The triglyceride:HDL pattern describes how fat and carbohydrate are currently being handled. Fasting glucose, HbA1c and insulin describe glycaemic control. Thyroid function (TSH, Free T4) is a primary regulator of metabolic rate and a common reason a starting point reads wrongly. Where a marker has a recognised clinical cutoff, that is the figure quoted; where it does not, it is labelled as a functional range.

Organic Acids Test · Krebs Cycle

Mitochondrial Oxidation Pattern

Krebs cycle intermediates show where energy production is currently running well or bottlenecked. Elevated adipate and suberate point to impaired mitochondrial fatty acid oxidation, which matters directly if a high-fat approach is being considered. Methylmalonic acid gives functional B12 status. These describe present mitochondrial function; no organic acid pattern has been shown to identify an oxidative type.

DUTCH Plus · Hormone Panel

Autonomic and Adrenal Pattern

The cortisol diurnal curve describes current HPA output and rhythm. Total cortisol metabolites give overall production rather than free cortisol alone. The DHEA:cortisol relationship describes anabolic against catabolic balance. Oestrogen clearance pathways are shaped by methylation status. HPA dysregulation is well established; adrenal exhaustion as a distinct downstream state is not, and is not claimed here.

An Important Distinction

Recognised pattern vs current function

Recognised Pattern

The pattern you recognise in yourself

The premise is that long-standing tendencies in appetite, energy, thermoregulation and stress response are stable enough to be recognised rather than discovered afresh each time. Nothing measures this, including the questionnaire. No genetic panel has been shown to identify a Metabolic Nature, and none is used to assign one. It is the pattern you recognise in yourself, taken as a starting hypothesis — and it is the part of the framework with the least evidence behind it, which is why the protocol never rests on it alone.

Current Function

What your findings show now

What the panels show now — HPA axis status, thyroid function, mitochondrial efficiency, nutrient cofactor availability, gut integrity. Where this disagrees with the recognised pattern, current function governs the protocol. Somebody whose questionnaire reads fast-oxidative, but whose panels show poor protein digestion, does not get told to eat more protein. Digestion is the constraint, and the constraint is addressed first. The disagreement is recorded in your summary, side by side, with the direction of the conflict named — not resolved quietly in favour of whichever instrument is more convenient.

HPA Axis Dysregulation

Sustained HPA activation produces sympathetic indicators on the questionnaire and on the panels. It does not leave one reliable reading and one distorted one — it makes both less trustworthy at once, which is why the starting point stays provisional until it clears. Address the HPA axis first, then reassess.

Gut Dysbiosis and Permeability

Systemic endotoxaemia from a permeable gut drives chronic inflammation that suppresses anabolic signalling and distorts nutrient absorption patterns. Somebody whose recognised pattern points toward a richer, fat-leaning plate may be unable to absorb or use it while the gut is compromised — which will read as the opposite pattern until the gut is addressed.

Nutrient Cofactor Depletions

Krebs cycle function requires B vitamins, magnesium, CoQ10, and iron. Depletion of any of these slows energy production regardless of the recognised pattern, so the panels will read slow while cofactors are insufficient. This is why the starting point is revisited after nutritional foundations are established.

Subclinical Hypothyroidism

Thyroid hormone is a primary regulator of metabolic rate. Low thyroid function, including a TSH toward or just past the upper limit of the laboratory’s reference range, can produce fatigue, weight gain and cold intolerance that will read as a slow pattern whatever the recognised pattern is. Thyroid function is checked and addressed before the starting point is treated as settled.

Why does every diet workfor someone — but not for everyone?

What this is, and what the evidence for it actually is

Two axes, three positions on each

Autonomic Nervous System Dominance

Cellular Oxidation Rate

Six positions across two axes —you are given one from each.

What the panels can tell you —and what they cannot

Recognised pattern vs current function

Why does every diet work
for someone — but not for everyone?

Six positions across two axes —
you are given one from each.

What the panels can tell you —
and what they cannot