How many times have you heard "I am really craving some ice cream. It must be because my body needs dairy or something"?
While this sort of belief is common, it is actually not scientifically proven. In fact, the reason that you might be craving a particular food is often linked to an emotional state, habit, simply just wanting an excuse to eat something in particular or the most scientific reason is likely to be because you are dehydrated.
So, next time you are craving something try having a glass of water and then see if you still feel like the food you were craving. If you are still in the mood for that ice cream, just keep the serving small!