It's like going to the grocery store on an empty stomach. Suddenly you want things that under normal circumstances you wouldn't want. You find things appetizing that you normally would not. Your are pushed to this point where animalistic survival seems to overwhelm your higher thoughts of selectiveness and judgement.
This is life and all things in it. We all have our list of things that make us happy. It starts from basic needs that all humans share and then grows when you factor in the needs of a particular personality. When you lack something in any certain aspect of your life you have a hole. You begin to try and fill it. Because most people do not analyze their own thoughts feelings and actions thoroughly, we end up trying to fill this hole of dissatisfaction with the wrong things. (ex. trying to fill the "security" or "love" space with sex). We have to try and remember what it is we are here for even though we are hungry and just want something to eat.
before you go to the "store"...make sure you have a list of what you need and make sure you eat something first.