J.Konstapel.Leiden,21-10-2026.
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A Reference Work on What the Body Needs, How It Is Grown, Prepared and Kept, and What Can Be Done With Simple Means © 2026 J. Konstapel, Constable Research, Leiden. All rights reserved. Quotation
Aanleiding: Regeneratieve landbouw is veelbelovend, maar ook nog een ‘enorme strijd’
De meeste boeken over voedsel kiezen een kant. Ze zijn óf voedingsleer, vol met referentiewaarden maar stil over waar eten vandaan komt. Óf het zijn boeken over landbouw, rijk aan bodem en seizoen, maar vaag over wat het lichaam nu eigenlijk nodig heeft. What Food Does Our Body Need van J. Konstapel (Constable Research, Leiden, 2026) weigert die splitsing. Het volgt één lijn: van het lichaam dat een stof nodig heeft, terug naar de grond waar ze groeit, en vandaar via de keuken naar het bord.
Wat erin staat
Het boek telt negen delen. Eerst wat het lichaam nodig heeft: energie, negen aminozuren, twee vetzuren, dertien vitaminen, mineralen, water — telkens met de waarden van EFSA en de VS naast elkaar. Dan de grond: wat levende bodem is, hoe je met de hand werkt, hoeveel uur een perceel kost. Dan wat je kunt telen, op hoeveel land, met welke opbrengst. Daarna kruiden, bereiden en bewaren — zonder koude keten. Vervolgens veertien dagmenu’s en recepten, voedingsstof voor voedingsstof nagerekend. Tot slot de mensen die het werk doen, en de ziekten die voedsel voorkomt.
Wat het bijzonder maakt
Het schat niet. Elk getal komt uit een genoemde bron of is zichtbaar uitgerekend. Is iets onbekend, dan staat dat er. Een lezer kan alles controleren.
Het twijfelt eerlijk. Elke bewering krijgt een graad: STRONG, MODERATE, WEAK of CONTESTED. Komen goede bronnen niet overeen, dan worden beide cijfers afgedrukt. Dat levert opvallende uitkomsten op. Antioxidantpillen: geen bewijsvoering, mogelijk schade. Foliumzuur vóór de conceptie: zeventig procent bescherming. Vitamine D-pillen voor wie geen tekort heeft: geen effect.
Het is tegen zichzelf gecontroleerd. De dagmenu’s werden voorspeld en vastgelegd met een cryptografische hash vóór het tellen begon. Daarna zijn ze vier keer nagerekend, met aparte code en tegen twee onafhankelijke voedingstabellen. Een externe toetsing van 129 willekeurige claims vond er geen enkele ontkracht.
Het stelt één praktische vraag. In elk deel: wat kan met eenvoudige middelen — weinig industrie, geen koude keten, weinig geld. Daaruit komt een van de mooiste inzichten van het boek: eenvoudig is niet hetzelfde als goedkoop. Een blik tomaten is goedkoop, maar de keten erachter is lang.
Wat je eraan hebt
In de keuken: eet het soepwater, giet het boonwater weg. Citroen bij de linzen, thee tussendoor in plaats van erbij. Bonen weken en hard doorkoken. Zuurkool op twee procent zout. Nooit gewone groenten wecken op 100 °C.
Voor wie wil begrijpen waarom: graan en peulvrucht sluiten elkaar af. Tarwe-eiwit haalt 57 procent van de lysine die het patroon vraagt, linzen-eiwit haalt 94 procent. Gemengd voldoen ze allebei. Erwtensoep met roggebrood is die biochemie in een kom.
Het net
Deel 0 leest voedsel door een beeld van een visnet onder spanning: alleen wat sluit, blijft bestaan. De auteur noemt dit zelf een “lezing”, geen mechanisme. Wie er niets mee heeft, kan het overslaan. Het boek verliest er niets door — de gemeten feiten dragen zichzelf.
Conclusie
Dit is een naslagwerk voor wie één boek wil dat loopt van microvoedingsstof via keuken en akker terug naar het bord. Gedisciplineerd in zijn bronnen, eerlijk over onenigheid, en bruikbaar zonder fabriek of vriezer. Met andere woorden: een boek om te hebben én om in te bladeren.
What Food Does Our Body Need, J. Konstapel, Constable Research, Leiden. Eerste druk, oktober 2026.
English Essay
Most food books choose a side. They are either nutrition manuals, full of reference values but silent about where food comes from. Or they are farm books, rich in soil and season, but vague about what the body actually requires. What Food Does Our Body Need refuses this split. It follows one line from start to finish: from the body that needs a nutrient, back to the ground that grows it, and forward again through the kitchen and the store to the plate. That single line gives the book its unusual coherence. Nothing in it floats free.
The author is J. Konstapel of Constable Research, Leiden. The work is a first edition, dated October 2026, running to 73 pages in nine parts with three appendices. This essay sets out what the book contains, what makes it unusual, what it can be used for, and where its sources lead the reader who wants to go further.
What the Book Contains
The nine parts trace the full length of the food chain.
Part 0 supplies the frame. The author reads food through an image of a fishnet under tension, drawn from his own Vacuum.Net theory. Only what “closes” — what returns onto itself in phase — persists. Digestion is read as a test applied at successive depths: mouth, stomach, small gut, colon. Fibre is the clean example. The body does not absorb it, so it passes through unchanged and the colon microbes read it instead. The author is careful to call these “readings”, not mechanisms. The frame orders the facts. It does not claim to cause them.
Part 1 states what the body needs, in grams, milligrams and micrograms. Energy. Protein and the nine essential amino acids. Two essential fatty acids. Thirteen vitamins. A set of minerals and trace elements. Water. The chapter works with two reference persons: a man of 70 kg and a woman of 60 kg, both aged 30–39 and moderately active. Every value is given twice, once from the European Food Safety Authority (EFSA) and once from the United States, with Dutch values where they differ.
Part 2 turns to the ground. What soil is. How it is worked by hand. How much work a plot demands. How nutrient loops close. Whether the soil changes the food — the selenium chain from rock to grain to body is the book’s clearest case.
Part 3 answers what to grow. Dutch yields per crop, land per person, hours per square metre. It compares diets: a potato minimum, a plant diet at Dutch and organic yields, and the EAT-Lancet planetary health diet.
Part 4 treats the herbs, with the European Medicines Agency monographs set against Cochrane reviews.
Part 5 treats preparation: what cooking adds, what it destroys, how anti-nutrients such as phytate are removed by soaking, sprouting and sourdough, how fermentation works, what salt does, and when to eat.
Part 6 treats keeping without a cold chain: cellars, clamps, drying, lactic fermentation, bottling, freezing, and the safety rules that come with each.
Part 7 delivers fourteen counted day menus and a set of recipes — erwtensoep, hutspot, zuurkoolstamppot, dal, hummus, kale with chickpeas — each with nutrients computed per serving from the USDA table.
Part 8 looks at the people who do the work. Farming in the Netherlands now employs about 100,000 people for 18 million inhabitants. The book asks what knowledge left the land with them, and what one hour a week from two million people would cover.
Part 9 links food to the illnesses it prevents, condition by condition, each with a measured effect and an evidence grade.
Three appendices close the book: the core reference tables, a register of disagreements and open questions, and 88 annotated references.
What Is Unusual About It
1. It refuses to estimate
Every number in the book was taken from a named source or computed from such numbers. Where the arithmetic is the book’s own, the sum is shown. Where a value is not known, the book says so plainly. It does not fill the gap with a guess. This discipline is rarer than it should be, and it changes how the book reads. A reader can check anything.
2. It grades its own claims
Every intervention carries a grade: STRONG, MODERATE, WEAK or CONTESTED. When good sources disagree, both figures are printed. The supplement section is a model of this. Antioxidant pills, across 78 trials and nearly 300,000 people, show no benefit and possible harm — STRONG. Folic acid before conception cuts neural tube defects by about 70 per cent — STRONG. Vitamin D in people who are not deficient prevents neither cancer nor cardiovascular events — STRONG. The justified supplements turn out to be few and narrow: folate around conception, vitamin D for defined groups, vitamin K for newborns, B12 for those who eat no animal food.
3. It prints the disagreements
Appendix B is a register of open disputes, stated without embarrassment. The US and EFSA differ on B12, folate, iron in pregnancy and vitamin B6. The two main composition tables disagree about the vitamin D in herring by a factor of four, and about folate in lentils by a factor of more than four. Meta-analyses disagree about the yield cost of no-till. The book prints both sides and keeps working. This is what an honest reference work looks like.
4. It was checked against itself
The Methods section is remarkable. Seven research lines, each with every claim recorded and sourced. The fourteen day menus were predicted in writing and locked with a cryptographic hash before any nutrient was counted; the counting script refused to run without the matching hash. The menus were then counted four times: against two releases of the USDA table, once with separate code using exact fractions (largest difference: 0.029 per cent), and once against the independent UK CoFID table. An independent judge then sampled 129 claims at random and reopened their sources: 115 confirmed as written, 12 confirmed with a correction, none refuted. A book that submits to this has earned the right to be used.
5. Its question is practical, not academic
Every part asks the same question: what can be done with simple means — little industry, no cold chain, little money? Where a long chain is genuinely needed, the book names the link that cannot be shortened. This keeps the work grounded. It also produces its most quotable insight: a simple means is not the same as a cheap means. A tin of tomatoes is cheap. The chain behind it is long.
What Is Useful In It
For the household. The book is full of sentences a kitchen can act on. Eat the soup water; pour away the bean water. Put lemon on the lentils; drink the tea between meals, not with them. Soak beans and boil them hard. Ferment at two per cent salt. Never bottle plain vegetables in a water bath at 100 °C. Cure before you store. Keep apples away from vegetables. Each of these is measured, not merely asserted.
For the grower. Part 2 and Part 3 give Dutch yields, organic yield gaps of 19–25 per cent, the hours per square metre of hand-scale growing from the best-documented market-garden study, and the land a person needs under each diet — from 340 m² for a potato minimum to 1,827 m² for EAT-Lancet. The arithmetic for a whole country is laid out: a plant diet at organic yields fits on the farmland the Netherlands already has.
For the eater who wants reasons. The cereal-and-legume finding is worth the price alone. Wheat protein reaches 57 per cent of the FAO lysine pattern; lentil protein reaches 94 per cent of the sulphur-amino-acid pattern. A 50:50 mix meets both. Erwtensoep with rye bread is not a tradition with a story attached. It is that biochemistry served in a bowl.
For the professional. The reference tables align EFSA, US and Dutch values in one view. The nutrient-retention table and the annotated bibliography function as a desk aid. Part 9’s condition-by-condition table, with measured effects and grades, is a compact bridge between food and clinical prevention — including the finding that several old prohibitions were wrong: low-calcium diets for kidney stones raised recurrence, and forbidding nuts and popcorn in diverticular disease had it backwards.
The Sources
The reference list is not decoration. It is the book’s second half. Each of the 88 entries carries a note on why it is worth reading and, where useful, how to read it. The reader is directed, among others, to:
- The EFSA dietary reference values — the summary report and the individual panel opinions on protein, fats, carbohydrate and fibre, vitamin D, B12, iron, zinc, iodine and thiamin. These are the backbone of Part 1.
- The Lancet fibre series (Reynolds et al., 2019): 185 cohort studies and 58 trials, the main dose-response evidence that 25–29 g of fibre a day is where the benefit lies.
- The Cochrane reviews that settle or unsettle the claims: antioxidant supplements, folic acid, echinacea, St John’s wort, garlic.
- The founding trials: the MRC Vitamin Study of 1991 on folic acid; the Salt Substitute and Stroke Study in the New England Journal of Medicine; the VITAL and D-Health trials on vitamin D.
- The agricultural canon: the Rothamsted Broadbalk experiment running since 1843; the meta-analyses of no-till, organic yields, earthworms and intercropping; Poore & Nemecek’s environmental footprints in Science; the EAT-Lancet Commission.
- The Dutch sources: CBS harvest statistics, the RIVM food consumption survey, the Gezondheidsraad guidelines, Wageningen research on compaction and labour.
- The food-science tables: the USDA nutrient retention factors, the USDA and CoFID composition tables, the FAO work on maize and on vitamin and mineral requirements.
- The author’s companion works, including Where Illness Comes From, Completed, from which Part 9 draws.
Where the Reader Can Go Further
The annotated list is built to be followed. A reader with the book in hand has several clear paths:
- Into the reference values. Start with the EFSA summary report, then open the single opinions behind any value that matters to you. The book tells you which opinion carries which number.
- Into the fibre and supplement evidence. The Reynolds series and the Bjelakovic Cochrane review, read together, reorganise a supermarket aisle.
- Into the soil debate. Read Pittelkow on no-till, then the statistical re-analysis that halves the estimated yield loss. Then Rothamsted, for the longest test of manure against fertiliser in the world.
- Into diet scenarios. Poore & Nemecek for environmental cost per food; Peters et al. for why a lacto-vegetarian diet can feed more people than a vegan one; EAT-Lancet for the planetary health diet the book uses as its Diet A.
- Into the kitchen science. The USDA retention factors table, the sourdough-phytate work of Lopez et al., the Hong Kong and FDA rules on kidney beans, and the pH 4.6 rule behind safe home bottling.
- Into the disputes. Appendix B is itself a research programme: herring vitamin D, lentil folate, cover crops and soil carbon, the mechanism of lime-treated maize. Each entry names both sources.
An Honest Reservation
Two things should be said. The Vacuum.Net frame of Part 0 will not be to every taste, and the author knows it; he marks each use of it and repeats that a reading is not a mechanism. The frame can be skipped without loss. And some sources could not be reached — the book says which, and lists what remains open. These are flaws of transparency, not of concealment. They argue in the book’s favour.
Conclusion
What Food Does Our Body Need does three things at once, and does them carefully. It states, in plain numbers, what a body must obtain from outside itself. It follows each of those numbers back to a soil, a seed, a season and a pair of hands. And it asks, throughout, what can be done without a long industrial chain. It is disciplined about evidence, honest about disagreement, and checked to a standard most trade books never approach. For the reader who wants a single volume that runs from the micronutrient to the kitchen to the field — and back to the plate — this is a book worth having, and worth following into its sources.