There are many other intolerances, e.g. coeliac disease and the many different kinds of food allergies.

Besides these cases, which are obvious due to immediate harm, and which are the reason for laws about food labeling that mentions lactose, gluten and various allergens, there is a lot of variability between humans in the efficiency of digesting various foods and in the capacity of absorption for various nutrients.

Some people are able to eat pretty much anything, while others are aware that they do not feel well after eating certain things, so they avoid them.