People talk about things like chocolate or ice cream as if they were magical gifts from the Gods designed to lead us into temptation and dash our plans for healthy living. They are not magical. They are just another foodstuff amongst loads of others. They don’t have a supernatural hold over us.
Your body responds to these foodstuffs because repetitively, over time, we gave it the message that if you need these nutrients, then this is what you should be looking for. Like coffee for instance. If you tend to drink coffee throughout the day rather than water, then we’re teaching our body that coffee = water. So whenever your body is thirsty, you get a big picture of coffee in in your head.
Of course, by the time our body actually tells us we need fluid, our reserves are pretty low. If we had remembered to drink water though out the day BEFORE we were thirsty, or body would never need to send fragrant frothy pictures of cappuccinos into our heads in the first place.