Every few years, a dietary approach achieves cultural dominance. Low fat. Low carb. Paleo. Keto. Carnivore. Plant-based. Each one has its passionate advocates — people for whom it genuinely transformed their health. And each one has its disillusioned dropouts — people who followed the same rules meticulously and felt worse.
This pattern repeats itself because the nutrition conversation almost never asks the right question. The question isn't which diet is correct. The question is which metabolic system is it operating on — and whether those two things are compatible.
That distinction is the foundation of everything I've put into Metabolic Natures.
The core observation: not everyone processes food the same way
The idea of metabolic individuality isn't new. Roger Williams — the biochemist who identified pantothenic acid and coined the term biochemical individuality — was arguing in the 1950s that individual variation in physiology was so pronounced it should be the starting point of any nutritional investigation, not an afterthought.
What was missing then, and has largely remained missing, is a workable clinical framework that connects metabolic type to functional test findings. Francis Pottenger's work on the autonomic nervous system, early in the twentieth century, and George Watson's on oxidation rate in the 1970s each proposed a way people differ — proposed, not established. Bill Wolcott's Healthexcel system combined the two into a dual-axis model.
What the earlier systems did not have is the functional laboratory data now routinely available. Metabolic Natures uses a comprehensive blood chemistry panel, an organic acids test and a DUTCH hormone assessment — not to confirm a type, because no test has been validated against one, but to describe what someone’s biochemistry is doing now and to change the protocol accordingly.
"The person who does well on a richer, lower-starch plate is not the person who wilts on it. The framework is a way of recognising which of those you have always been — and then checking it against what your biochemistry is doing now."
The six Metabolic Natures
The framework uses six names, and they are not six kinds of person. They are three positions on each of two axes. You get one position from each, with a percentage on each, in the fixed order oxidative first and autonomic second — so a reading is 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. See both axes on one page → Why that changed →
Axis 1 · Oxidative — how rich and starchy meals land
The name comes from the tradition’s reading of this pattern as a fast or slow oxidation rate. Nothing here measures how fast you burn fuel; the reading is built from how you say meals affect you. It sets the balance of starch and fat. Protein is not on this axis: it is set by your body weight and is the same on every plate.
Axis 2 · Autonomic — activation against recovery
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.
Why the questionnaire is not the whole picture
The questionnaire is the closest available proxy for the way you have run for years — a starting hypothesis, not a measurement. But answers are coloured by the present too: a hard few months, a medication, a gut that is not coping. That is why testing is used alongside it — not to overrule the questionnaire about who you are, but to find what is in the way now.
Functional testing describes the current state. Blood chemistry, read against the laboratory’s reference ranges with any functional range labelled as one, shows bicarbonate and CO₂, total protein and albumin, and the triglyceride-to-HDL pattern. The organic acids test adds mitochondrial data — how efficiently the Krebs cycle is running and where the bottlenecks are. The DUTCH assessment adds the adrenal and sex hormone picture, which is inseparable from metabolic rate.
This page previously listed a calcium-to-phosphorus ratio and an eosinophil-to-basophil ratio here as type markers. Both have been removed. The Ca:P ratio came into this framework from hair tissue mineral analysis, where it is a hair measure read as an autonomic ratio — not a serum measure of oxidation rate, which is how it was presented here. The eosinophil-to-basophil ratio returns nothing in PubMed as an index of autonomic tone under any framing tried. The full correction, with sources, is here →
None of these tests were designed with metabolic typing in mind, and none has been validated against an axis position. What they do is describe current function — enough to change a protocol, not enough to confirm a position. Where the test picture and the questionnaire disagree, current function governs the protocol until the constraint clears.
Long-standing pattern versus current function
One of the more important — and frequently muddled — questions is whether your position is fixed or changeable. The honest answer is that we do not know how fixed it is, and that the distinction that actually matters clinically is a different one.
Long-standing pattern is the way you have run for years, across different diets, jobs and life stages — the thing you recognise when you read it back. The questionnaire is the closest available proxy for it. It is a starting hypothesis, not a measurement.
Current function is what your biochemistry is doing now: HPA axis status, thyroid function, mitochondrial efficiency, nutrient cofactor availability, gut integrity. Someone who has run fast for thirty years can present as slow under sustained load. Where the two disagree, current function governs the protocol until the constraint clears.
This page used to say something different and stronger: that SNPs governing oxidative phosphorylation, beta-oxidation and the electron transport chain establish a fixed genetic type underneath. That claim has been removed. It probably has some genetic component — most physiological variation does — but no SNP panel has been tested against oxidative or autonomic position, none is used here, and anyone selling you a gene test for your metabolic type is ahead of the evidence. The correction is here →
And "until the constraint clears" has to mean something checkable, so it does: the markers that define the constraint are named in advance, in writing, before the protocol starts, along with what change is expected and by when. They are retested. Four outcomes are possible, and all four are recorded: the constraint clears and the picture shifts as predicted; the constraint does not clear; the plan was not followed, which is recorded as untested rather than failed; or the constraint clears and the expected shift does not happen. That last outcome is the one that counts against the reading, and two cycles of it mean reconsidering the reading rather than adding another intervention.
What this means in practice
If you've tried multiple dietary approaches and each one has produced either a modest short-term improvement or an outright worsening, the most useful question isn't "which diet should I try next?" It's "do I actually know what metabolic system I'm working with?"
Someone reading fast on the oxidative axis who has been living on starch-led meals may find a plate with less starch and more fat steadies them. Someone reading slow who has been told to go ketogenic may find the opposite. Protein stays set by body weight in both. Those are the framework’s starting hypotheses, drawn from clinical observation — which is why the expected change is written down before the plan begins, and checked.
Neither is a failure of willpower. And if the change that was written down does not happen once what was in the way has cleared, that counts against the reading — it is not explained away.
"The questionnaire says where to start. Testing says what is in the way. The written prediction says whether it worked."
Where to go from here
The book is now Metabolic Natures, Volume 1: Your Reading, Your Plate, written to the current method. It replaces the earlier edition, which described what the questionnaire and the tests measure the wrong way round; the dated correction lists the places.
If you want to understand your own metabolic picture through functional testing — blood chemistry, organic acids, and DUTCH — the TDG Five-Test Programme at Detective Health includes full practitioner interpretation and a personalised written protocol based on your results, including a Metabolic Natures reading.