Case Study 2 — Twenty-Three Foods: What the Panel Actually Measured

A composite clinical case. ⚠️ The IgG panel's biology, the professional-body position and the consequences of multi-food elimination are real; the person is constructed. No specific commercial test is described.

Setup

Corinne Bettancourt is 41. She has had bloating, fatigue, headaches and intermittently loose stools for about five years.

She has seen her GP four times. Bloods were unremarkable. She was told it was probably stress, then probably IBS, and given a leaflet.

⚠️ That is the context for everything that follows, and it is not a criticism of the GP so much as a description of what a five-year non-answer does to a person.

Fourteen months ago she paid £249 for a food intolerance test — a finger-prick sample, posted off, results in three weeks.

⚠️ It reported reactivity to twenty-three foods.

The list

In descending order of "reactivity," as printed:

Cow's milk · yeast · egg white · wheat · egg yolk · almond · gluten · cheddar · yoghurt · cashew · soya · oat · barley · rye · kidney bean · tomato · cucumber · banana · lentil · brazil nut · rice · pea · garlic

⚠️ She eliminated all twenty-three, the day the report arrived.

"It was such a relief. Five years of being told nothing was wrong, and here was a list."

What the panel measured

⚠️ IgG antibodies to food proteins.

IgG to food is a normal, expected immune response to something you eat. ⚠️ It is a marker of EXPOSURE — and, on the current understanding, possibly of TOLERANCE.

Which produces a finding that is uncomfortable once you see it:

⚠️ And near the bottom: brazil nut, which she ate perhaps twice a year.

💡 Aha moment. ⚠️ The test ranked her diet.

The strongest "reactivities" were the foods she ate most often. The weakest were the ones she barely touched.

⚠️ That is not a flaw in the assay — the assay worked. IgG rose in proportion to exposure, exactly as the biology predicts.

The flaw is in what the report claimed the number meant.

⚠️ Major allergy and immunology professional bodies have issued explicit position statements advising against food-specific IgG testing for diagnosing food allergy or intolerance. This is not a fringe objection.

Why it appeared to work

⚠️ Because it did work, for about five months. And that is the hard part of the case.

Removing twenty-three foods removed:

⚠️ Her bloating improved substantially. So did her energy.

⚠️ Chapter 17's bundled intervention, Chapter 22's slot problem, and Chapter 27's FODMAP mechanism, arriving together — and all of it credited to a printed list of twenty-three foods.

The test appeared validated by the outcome. It wasn't. The bundle was.

What it cost by the time she came in

⚠️ That last row is the serious one.

She removed gluten fourteen months ago without ever being tested. ⚠️ If she has coeliac disease — and she has iron deficiency, fatigue and GI symptoms, which is a textbook presentation — she now cannot be diagnosed without a gluten challenge she is extremely unlikely to agree to (§28.6).

⚠️ The panel's most serious harm was not the twenty-three eliminations. It was the diagnosis it prevented.

What we actually did

⚠️ Not "that test is nonsense," which was true and would have failed.

Chapter 17 §17.13's rules: concede the true part, ask about the mechanism, decompose the bundle.

1. ⚠️ Conceded the true part first. "You've had five years of being told nothing was wrong, and something clearly is. And you did feel better — that's real."

2. ⚠️ Asked her to find brazil nut on the list, and asked how often she ate it. Then milk. She got there herself in under a minute.

"…It's just what I eat."

3. ⚠️ Decomposed the bundle — the six rows above. She recognized every one.

4. ⚠️ Urgent: the coeliac question. Explained honestly, including that the window had closed and what reopening it would cost. She is considering it.

5. Screened for the deficiencies the restriction had produced — ferritin, B12, calcium intake, vitamin D.

6. ⚠️ Referred for a structured FODMAP process with reintroduction (Chapter 27 §27.11) — which is what she should have been offered five years ago.

7. ⚠️ And named the trajectory. "The list has gone from twenty-three to thirty-one. That direction is the finding." Chapter 34 was raised, gently.

Ten months later

⚠️ She did the challenge. It was unpleasant and it took six weeks. She is not coeliac — which is enormously reassuring and which she could have known in a fortnight fourteen months earlier.

What she said:

"The maddening thing is the test wasn't the problem. The problem was that nobody had given me anything else in five years, so when something arrived with numbers on it, of course I took it."

Analysis

1. ⚠️ The test ranked her diet. Strongest reactivities were her most-eaten foods; brazil nut, eaten twice a year, was at the bottom. The assay worked; the interpretation didn't.

2. ⚠️ Five years of non-answers is the precondition. The panel succeeded because it was the first thing that offered specificity.

3. ⚠️ It appeared to work because it removed a bundle — UPF, eating out, alcohol, four FODMAP groups, late snacking, and ~400 kcal.

4. ⚠️ The list grew from 23 to 31, because when symptoms recurred the learned response was to remove more. That trajectory is §28.11's signature.

5. ⚠️ THE MOST SERIOUS HARM WAS THE PREVENTED DIAGNOSIS. Gluten removed without testing, in someone with iron deficiency, fatigue and GI symptoms.

6. The nutritional damage was measurable — fibre 12 g, low ferritin, low calcium, 6 kg unintentional loss.

7. ⚠️ Two dose-dependent FODMAP triggers, found by the process she should have been offered five years earlier — and her symptom control is comparable on a normal diet.

8. And her own analysis was the best one in the file. ⚠️ "Nobody had given me anything else in five years." Which makes this a failure of the pathway before it was a failure of the test.

Discussion Questions

1. ⚠️ "The test wasn't the problem — nobody had given me anything else." How much of this sector's success is explained by unmet need rather than by persuasion? What follows for how to respond to it?

2. She found the answer herself in under a minute when asked about brazil nut. ⚠️ Why is a self-discovered gap more durable than a stated one? (Chapter 17 §17.13.)

3. ⚠️ The most serious harm was a prevented diagnosis. Design the warning that should accompany every commercial food-intolerance test. Under 30 words. Would it work?

4. The list grew from 23 to 31. ⚠️ At what point does this become Chapter 34's territory? What are the markers, and who should notice?

5. ⚠️ Professional bodies have issued explicit statements against IgG testing and it remains widely sold. Why? What would change it — regulation, professional pressure, or better pathways?

6. ⚠️ She underwent a six-week gluten challenge to get a negative result. Was that worth it? What would you have advised, and does the answer depend on the result you got?

Your Turn

⚠️ For anyone holding a food intolerance test result, or considering one.

Step 1 — ⚠️ The exposure test, and it takes two minutes.

Take your report. Find the top five "reactive" foods. ⚠️ How often do you eat each of them? ____

Now find the five at the bottom. ⚠️ How often do you eat those? ____

⚠️ If the strong results are your staples and the weak ones are things you rarely eat — the test ranked your diet.

Step 2 — What did it actually measure?

⚠️ IgE, IgG, or something else? ____

⚠️ If IgG: it measured exposure. If it doesn't say, that itself is informative.

Step 3 — ⚠️ The urgent screen, before anything else:

• [ ] ⚠️ Have I removed gluten without being tested for coeliac disease? → ⚠️ This is the priority. §28.6
• [ ] Do I have iron deficiency, unexplained fatigue, or unintentional weight loss? → See someone
• [ ] Have I had a rapid reaction with breathing or circulatory symptoms? → Allergy assessment

Step 4 — Decompose your bundle. ⚠️ List everything the elimination removed BESIDES the named foods.

Ultra-processed food · eating out · alcohol · FODMAP groups · snacking · calories · attention.

⚠️ Count them. If it's more than three, nobody can learn anything from the result — including you (Chapter 17, shape 8).

Step 5 — ⚠️ The trajectory question:

Foods on my avoid list when I started: _ · Now: _

⚠️ If it has grown, that is the finding, and it is more important than any individual food on it.

Step 6 — And ask for the thing you should have been offered:

⚠️ Coeliac serology while still eating gluten · a structured FODMAP process WITH reintroduction · and a look at ferritin, B12, calcium and vitamin D.

Three things. All of them give food back rather than taking it away.