Something similar has happened to cooking, a subject highlighted by celebrity chef Prue Leith on her appointment last week to chair the School Food Trust. Its remit is to improve school meals, which ministers blame for youthful obesity. But like most quangos, it wants to raise its profile and extend its territory.
So Leith will campaign to make school cookery lessons compulsory.
Yet the vast majority of the human race prepared its own food for thousands of years without benefit of home economics or food technology lessons. In most Continental countries, people still do so and would find it extraordinary if schools taught a subject that could easily be learnt at home.
Schools, I fear, are part of the problem, not the solution.
Healthy eating is really very simple: get hold of fresh, locally grown ingredients and the food will do you good and taste good at the same time.
And food can be perfectly enjoyable without complicated recipes. Any basic cookery book published within the past century will tell you all you need to know.
The glossy books marketed by Ms Leith and other celebrities - full of obscure ingredients, expensive utensils and dishes that look like works of art - set goals which most people cannot hope to attain. So they give up and send out for chicken tikka masala.
Schools contribute to this sense that food is something complicated and possibly dangerous. They imply you should not go near a cabbage until you fully understand its cell structure. Professional educators have tried to turn cooking into a "proper subject" (just as they would with driving if they had the chance) and have dressed it up, at various times, as economics, science, and now design and technology.
Ofsted has spelt out the results. Food technology lessons are over-weighted with theory and written work, with little time for practical food preparation. Moreover, the subject - though there are plans to give it an overhaul - focuses, at present, on the design, development and marketing of products. It reinforces the child's belief that nobody could possibly want to eat food unless it comes out of a packet and that, as the course title suggests, food and technology are inseparable.
If we want our children to eat better, we should teach them something that does require sophisticated knowledge and skill - gardening. They will thus learn how to put healthy food on their tables while enjoying some vigorous exercise. We shall then have in place both the main requirements for conquering obesity.l email@example.com