I have found that I start to "hunger" for things like Dairy Queen (when I'm not hungry) when I keep seeing banner ads on the sides of facebook and other websites that I search. So I minimize the browser window to a smaller setting, so I can see what I want, and miss all those pesky ads. The power of seeing a familiar logo sets me craving for things not good for me and this is how I prevent some of that.
I have noticed that for the most part, the banner ads on Spark People have been better than most, when coming to foods/cravings. This works mostly for the side ads and maybe not so much for the banner ads on the top and bottom of pages