My eating habits improved considerably once I made the commitment to get at least five servings of vegetables/fruits per day. I often get more than that. I haven't given anything up -- I do enjoy the occasional cheeseburger or pizza -- but by ensuring that I get enough veggies and fruits, I rarely find myself craving "bad" food the way I used to.

p.s. - I have been losing roughly a pound a month since I made this change about 15 months ago.