Some decades ago I was in a situation where I was cooking meals for a child who was allergic to eggs and for medical reasons couldn't eat dairy foods or acidic foods. It was a creative challenge to produce meals which were edible for the whole family yet still fitted in with the child's needs. As I was working full time, I did not have time to create two different dishes for every meal so we all ate the same meals.

As an example, spaghetti bolognese and lasagne were out because of the tomatoes and cheese, not to mention having to check whether the pasta was egg based. Eggs for breakfast, eggs in pancakes or cakes or in vege or salmon fritters, all out. Tomatoes and lemon juice were out. Orange juice was out. Just about every recipe that I tended to cook normally had to be re-thought or abandoned.

Cutting out one type of food is do-able, but cutting out three broad types makes it difficult.