I would suggest just focusing on what you can eat rather than what you can't. As Thud says, it's easy to fall into a negative mindset when you think too much about what you're missing out on. But on the other hand, think of all the other things you can eat that you might previously have been told were "bad". (Insert fatty dish of choice here. )

It gets easier once you've cultivated enough good eating options; with enough time the old urges will fade...