1936. Saskatchewan starts growing rapeseed, and nobody eats it. Then the war arrives and the navies have a lubrication problem. Steam turbines run wet, and ordinary lubricants slide off wet metal. Rapeseed oil does not. It clings to a wet surface better than anything else available, which makes it, for about six years, a strategic material. Canada plants it by the thousand acres. The oil goes into the engines of ships. Then the war ends. The ships stop needing it. Canada is left with a crop, a farm lobby, a crushing industry and no customer. There is an obvious customer sitting right there, three times a day. The problem is the oil. Rapeseed oil is 40 per cent or more erucic acid, and by 1956 the questions about erucic acid have turned awkward: fed at high levels, it produces lesions in the heart muscle of animals. Health and Welfare Canada recommends conversion to low erucic acid varieties. Read that sentence again in the right voice. This is not a food that developed a health claim. This is a lubricant that developed a mouth. So they breed it. Through the early 1960s Canadian plant breeders isolate lines low in erucic acid. In 1968 Baldur Stefansson at the University of Manitoba produces one. In 1973 the industry agrees, voluntarily, to cap erucic acid at 5 per cent in anything sold as food. In 1974 come the first double-low varieties, with the erucic acid down and the glucosinolates down: the two things that had made the plant unfit for a human being to eat, bred out to specification. The oil is now technically edible. It still has a name problem. In 1979 the Western Canadian Oilseed Crushers Association registers the solution: canola. Canadian oil, low acid. Six years after that, in 1985, the American regulator draws the formal line and blesses it. Rapeseed oil is for industry. Canola oil is for humans. Same flower. Same yellow field you drive past in May. Same seed, bred down and given a passport. Within twenty years it is one of the most consumed fats on earth, a heart-health icon, sold at eye level in a clear bottle, recommended from the good chair in the consulting room, poured into everything from crisps to infant food. None of this is hidden. Every step is in the agricultural record: published, dated, dull, uncontested. A wartime engine lubricant with a heart-lesion problem was bred, renamed, reclassified and sold to you as the healthy option, and the whole operation took forty years and required nobody to tell a single lie. They just needed a name you wouldn't ask questions about.