[[File:Sancho Panza starved.jpg|thumb|left|Sancho Panza being starved by his own physician]]
Sancho would fire the doctor right after his first meal. And while this one is fictitious, real-world dietitians wishing who wanted to keep their jobs must have, too, learned had to learn how to adjust the medical theory to their employers' expectations and how to come up with dishes that are not only healthful, but also tasty, in line with religious commandments, available in their the local climate and, last but not least, allowing them to show off their affluence.
Actually, let's start with that last criterion: how can dietetics help maintain the current (God-given) social order? How do you make sure that peasants and town folk don't even dream of eating the same food that the nobility does? One way, which has been practised for a long time, is to simply forbid them to eat above their station by enacting sumptuary laws. But it's not a very effective one; tell a man this or that dish to elite for him to eat and he will make a point of eating it only to show that he does belong to the elite. But what if you make him believe that such food unhealthy for him? This is where the dietitians come in. All they've had to do is to demonstrate that the humoral constitution of those who engage in physical labour, in close contact with earth and sun, is completely different than in those born not to work. And if so, then, absolutely logically, whatever is healthy for the latter is deleterious to the former and vice versa. Farmers, porters, soldiers and sailors should never consume fresh white bread, poultry or fruits, as these foodstuffs, while perfectly good for the high-born, would only serve to plaster their stomachs. And, conversely, the kind of food that befits working people, such as stale rye bread, gruel, cheese, salted herring, legumes and root vegetables, would be completely indigestible for the higher tiers of the society.