The late US president Ronald Reagan famously tried to justify cuts to school lunches for poor children by positing that ketchup was a vegetable.
Further expenditure on this food group was therefore unnecessary.
This week's highly detailed proposals for regulating school food (page 8) should put paid to any such "let-them-eat-cake" arguments on this side of the Atlantic once and for all. Do chips constitute a balanced meal? Is chocolate good for you? Should junk food be available in schools? The official answer is no.
For as Reagan's glib remark demonstrates, food is not just about nutrition, it's also about class and privilege. It has been well documented that if you live in a poor neighbourhood, fresh fruit and vegetables are harder to find and cost more in local shops than in middle-class areas.
In Finland, where the differences between rich and poor are less extreme than in most parts of the world, school meals are healthy and free. It would simply not occur to a Finn that cola or crisps should appear in a school canteen.
Here, it is more complicated. Even middle-class children don't want to eat salad, and there is a danger that youngsters will simply reject healthy food at school, and pick up salty snacks from the newsagent on the way in.
And are all these proposed regulations yet another symptom of the encroaching nanny state?
Maybe. But food is part of education. Children learn about nutrition in class, and schools should practise what they preach. After all, you are what you eat, and children are calmer and more focused when they have eaten nutritious food. Schools often have to hold firm to what they believe in even when it runs counter to the culture the children are immersed in at home. They teach tolerance even though some parents are racist. They teach compromise and discussion even though violence may be rife outside the school gates.
And any Jewish mother will also tell you that food is about love. Sometimes it has to be tough love.