Having a craving for something we define as "bad for us" usually means that we want something that doesn't serve us in some way (ex. craving fried food even though it gives us a stomach ache later).  However, if we crave anything, then it DOES serve us in some other way (ex. fried food providing temporary emotional comfort and tasting yummy!).  

When it comes to cravings, it is usually an EMOTIONAL desire that wins out over care for the physical body.  This usually means that your inner child and/or inner teenager (who are much more interested in feeling better in the moment) are probably speaking louder than your rational, long-term planning, adult self who believes in the value of choosing what serves the body in long-term health.

So, the key to being able to choose the option that does serve you over time is to find something that serves your long-term health that ALSO serves the desires of the inner child or teenager (ex. a nice bubble bath!).