01 — The Three Scales
What each score actually measures
They are different mechanisms. Histamine intolerance is a problem of degradation — too much dietary histamine, or too little of the enzyme (diamine oxidase) that clears it. Lectins are plant defence proteins that bind carbohydrate structures in the gut wall. Net carbs are neither: they are a measurement of what a food is made of. A food can be terrible on one axis and blameless on another, which is exactly why a single combined number would be worse than useless.
H Histamine
Source: SIGHI Food Compatibility List
Histamine content, plus histamine liberators, DAO blockers and other biogenic amines. Preparation matters enormously and mostly in one direction: freshness is the whole game.
- 0Well tolerated
- 1Small amounts usually tolerated
- 2Poorly tolerated
- 3Very poorly tolerated
L Lectin
Source: Plant Paradox lists, cross-checked against measured lectin-content literature
Lectin load — phytohaemagglutinin in legumes, wheat germ agglutinin in grains, nightshade and cucurbit lectins, A1 casein in cow dairy. 43 foods carry a preparation that genuinely lowers the score; the rest do not.
- 0Negligible
- 1Low
- 2Moderate
- 3High
K Net carbs
Source: USDA FoodData Central (SR Legacy), per 100 g
Total carbohydrate by difference, less fibre, less sugar alcohols. Unlike H and L this is not an estimate of how a food affects you — it is a measurement of the food. The bands are fixed thresholds, so any two people computing them from the same USDA row get the same answer.
- 0Under 3 g — eat freely
- 13–8 g — fits easily in a day
- 28–20 g — portion deliberately
- 3Over 20 g — breaks ketosis at any normal portion
02 — Evidence Quality
The two scales are not equally well evidenced
Read this before you treat the L score like the H score
The histamine layer rests on a long-standing clinical reference. The SIGHI Food Compatibility List has been maintained and revised for years by a patient-and-clinician interest group, is widely used in dietetic practice, and prints its own uncertainty — 125 of the 440 entries here are flagged uncertain because SIGHI itself marks them ambiguous or the sources disagree. Salmon, halibut, mahi mahi, scallops, squid, bone broth and fish oil are all live disputes.
The lectin layer does not have anything comparable behind it. There is real measured literature on lectin content in specific foods — phytohaemagglutinin in raw kidney beans is genuinely well characterised, and genuinely dangerous. But the leap from "this food contains lectins" to "this food harms people" is contested, the popular food lists are not systematically derived, and no equivalent of SIGHI exists to arbitrate them. Lectin ratings here should be read as a hypothesis to test on yourself, not a finding.
The tool never flattens the two into a single number, and neither should you. Where they conflict, the conflict is the information.
03 — The 143 Conflicts
Where the two protocols contradict each other
143 of 440 foods score well on one scale and badly on the other — 45 are histamine-clear but lectin-heavy, and 98 are histamine-flagged but lectin-clean. The tool has a filter that shows only these. The sharpest cluster is the grains: SIGHI rates wheat, bread, pasta, rye, barley and spelt as h0–1, while they sit in the top lectin tier with no preparation escape — wheat germ agglutinin is heat-stable, so cooking does not rescue them.
| Food | H | L | Preparation escape | Why they disagree |
|---|---|---|---|---|
| Wheat · bread · pasta | 1 | 3 | NO FIX | Low histamine; top lectin tier. WGA is heat-stable. |
| Rye · barley | 1 | 3 | NO FIX | Same grain mechanism as wheat. |
| Spelt | 0 | 3 | NO FIX | SIGHI's cleanest grain; still a top-tier lectin. |
| Quinoa | 0 | 3 | RINSE / PRESSURE-COOK | Histamine-clear pseudo-grain, saponin and lectin load. |
| Potato | 0 | 3 | PEEL / PRESSURE-COOK | Histamine-clear; nightshade lectin concentrated in skin. |
| Split peas · legumes | 1 | 3 | PRESSURE-COOK | Pressure cooking denatures phytohaemagglutinin. |
| Cashew nut | 1 | 3 | PREP | Technically a legume-adjacent seed. |
| Cucumber · bell pepper | 0 | 2 | PEEL + DESEED | Cucurbit and nightshade lectins sit in skin and seeds. |
| Whole milk | 0 | 2 | NO FIX | Fresh milk is histamine-clear; A1 casein is the lectin-side objection. |
| — and in the other direction — | ||||
| Salami · bacon · dry-cured ham | 3 | 0 | — | Curing and ageing build histamine. No lectin objection at all. |
| Dry-aged beef · smoked meat | 3 | 0 | — | Same mechanism: time and smoke. |
| Sauerkraut · fermented vegetables | 3 | 0 | — | Fermentation is a histamine factory; lectin-irrelevant. |
| Orange · lime · citrus zest | 3 | 0 | — | Classic histamine liberators; no lectin load. |
| Red wine | 3 | 0 | — | Histamine, liberator and DAO blocker at once. |
Representative rows. The full 143 are filterable inside the tool.
04 — The Ketosis Layer
A third scale that answers a different kind of question
This is the part most worth reading carefully. H and L are intolerance scales: they estimate how badly a food is likely to affect you, and the evidence behind them is contested — heavily so on the lectin side. K is not that. It is a macronutrient threshold derived from a published measurement, and nothing about the carb count is in dispute. What is disputed is whether a ketogenic diet benefits any particular person, and this tool does not answer that question and does not try to.
All three share a 0–3 shape because that makes them usable side by side. They do not share a meaning. A food rated H3 is one a histamine-intolerant person will probably react to; a food rated K3 is one that contains a lot of carbohydrate. Flattening those into a single verdict is exactly the failure this tool exists to avoid.
| K | Net carbs per 100 g | What it means | Foods |
|---|---|---|---|
| 0 | Under 3 g | Eat freely — will not move the needle | 194 |
| 1 | 3–8 g | Fits easily inside a normal day | 92 |
| 2 | 8–20 g | Counts against the budget — portion deliberately | 84 |
| 3 | Over 20 g | Breaks ketosis at any normal portion | 66 |
Four entries carry no K value at all — “leftovers”, “restaurant meals”, “smoked products” and “canned or semi-finished products”. Those are preparation states and categories, not foods, and no carb figure describes them. They were left blank rather than filled with a plausible-looking number.
The 52 foods that are clean on both intolerance scales and still break ketosis
This is the set the third scale exists to expose, and it is the one nobody predicts. These foods score H≤1 and L≤1 — genuinely fine on histamine and fine on lectins — and still carry enough carbohydrate to end ketosis. If you were running the two-scale version of this tool and eating to it, these are the foods that were quietly wrecking a ketogenic protocol while every indicator you could see said they were fine.
| Cluster | Count | Examples | Why it surprises |
|---|---|---|---|
| Fruit | 22 | Apple, blueberry, cherry, apricot, cranberry, date, pear | The low-histamine fruit list is almost entirely the high-carb fruit list. |
| Sweeteners | 9 | Honey, agave, fructose, glucose, maltose, lactose | Pure sugars are histamine-inert and lectin-free. They are still sugar. |
| Grains & starches | 6 | Rice, millet, tapioca, chestnut, rice noodles | The starches recommended as low-lectin escapes from wheat. |
| Beverages | 6 | Apple juice, cranberry juice, rice milk, cola | Liquid carbohydrate, no intolerance flag to warn you. |
| Nuts & seeds | 5 | Pistachio, sesame, pine nuts, poppy seeds, almond flour | Marketed as keto staples; several are not. |
| Vegetables | 3 | Leek, parsnip, sweet potato | The three root vegetables that pass both intolerance screens. |
| Other | 1 | Whey protein powder | Residual lactose in concentrates; isolates are near zero. |
Why the honest number here is 52 and not 69
69 foods are clean on H and L with a K of 2 or 3. Seventeen of them are spices and condiments — cinnamon, ginger, garlic, bay leaf, cloves, turmeric — and every one of those figures is correct per 100 g. Nobody eats 100 g of bay leaf. A threshold measured per 100 g describes the jar, not the spoonful, and reporting cinnamon as a food that breaks ketosis would be true arithmetic and useless advice.
So 55 entries carry a per 100 g marker. They still show their real number, and the tool still displays it, but the carb ceiling does not hide them and they are not counted in the 52. This is the one place where the raw computation is deliberately not the headline, and it is flagged rather than quietly adjusted.
05 — The Tool
What it does
Check a food. Search all 440 entries, or paste a whole ingredient list and have it scanned line by line. Preparation words move the scores in both directions: canned, smoked, cured, aged, deli, leftover, broth and pre-ground raise the histamine score; peeled, deseeded and pressure-cooked lower the lectin score, but only for the 43 foods where that preparation genuinely works. Filters cover a separate ceiling for each scale, category, keto-only, fixable-by-prep, and a toggle that shows only the 143 conflicts.
Build a menu. One, three or seven days from 46 recipes, with independent histamine and lectin ceilings, a keto filter and free-text exclusions. Every dish is re-scored at generation time. Recipes that depend on a lectin-reducing preparation are marked LECTIN PREP REQUIRED — in those, the peeling or pressure-cooking is doing the work and is not optional. Output includes a consolidated shopping list and a print stylesheet.
Runs entirely in your browser. Nothing you type is sent anywhere.
06 — Provenance
Where the numbers come from
- Histamine (H). SIGHI (Swiss Interest Group Histamine Intolerance) Food Compatibility List, cross-checked against the SIGHI elimination-diet leaflet, and against mastcell360 for the fish species SIGHI does not enumerate individually. Where sources conflict, the entry is flagged uncertain rather than silently resolved — 125 entries carry that flag.
- Lectin (L). Plant Paradox food lists, cross-checked against published measured lectin-content literature: phytohaemagglutinin in legumes, wheat germ agglutinin in grains, nightshade and cucurbit lectins, A1 casein in cow dairy. 43 entries carry a documented preparation mitigation. Lectin-side uncertainty is recorded in each entry's own note.
- Flags. Histamine liberators (118 entries), DAO blockers (27), other biogenic amines (93), and keto compatibility are tracked separately from the score itself, because a food can be low in histamine and still provoke a release. Cocoa and chocolate carry the DAO flag on the theobromine mechanism, not on a SIGHI marker.
- Net carbs (K). USDA FoodData Central, SR Legacy release — carbohydrate by difference, less total dietary fibre, less sugar alcohols. 341 entries are matched directly to a named USDA row, which is recorded on the entry itself; the remaining 95 have no USDA equivalent (pure sweeteners, additives dosed in milligrams, category placeholders) and carry a derivation with its basis stated in the open. No net-carb figure on this site was estimated without saying so.
- Method. Scores are integers 0–3 on all three axes and are never combined. A recipe's histamine score is the maximum across its ingredients; its lectin score is the maximum effective lectin value after any preparation the recipe actually specifies; its net-carb band is the maximum across the ingredients eaten in quantity, excluding the spices and condiments scored per 100 g. Recipe cards show that band rather than grams per serving, because the recipe data does not carry ingredient weights — only 16 of 278 ingredient rows specify one, and computing a per-serving figure from "1 tbsp" and "a pinch" would mean inventing it.
Important — please read
Longevity Command Center is educational content only. It is not medical advice, diagnosis, or treatment. Always consult your physician before starting any supplement, exercise, or health intervention. Nothing here has been evaluated by the FDA.
The net-carb figures are measurements and are as reliable as their USDA source. Whether a ketogenic diet is appropriate for you is a separate question that this site does not address and cannot answer — it is one for your physician, particularly if you are diabetic, pregnant, or taking medication that affects blood glucose.
Histamine tolerance and lectin sensitivity are both highly individual. Neither list is a verdict on any food. Both are starting points for a structured elimination-and-reintroduction protocol run with a clinician, and your own food and symptom log is the authority that overrides either of them. No food on this site is described as "safe" — every entry gives a score and the mechanism behind it, so you can judge it yourself.
If you are managing a diagnosed condition, are pregnant, or take medication that affects histamine metabolism, talk to your physician before changing your diet.