I know exactly what you mean! My urge to binge doesn't usually coincide with having good food around as I try not to keep anything "bad" in the house. So, I end up eating a bunch of stupid stuff that isn't all that good. It makes me feel like not only am I horrible at dieting, but I'm not even good at binge eating!
If I have an urge to binge at a supermarket, I walk around in a daze, not really knowing what to buy and I buy things that aren't all that good actually. What happens, actually, is that nothing tastes good enough. I am always looking for that amazing high and it's really hard for me to find it. I try to remind myself of this feeling when I have a craving. By the way, I think I told you before that I love your Avatar because I am REALLY into Nutella...I like to spread it on very good white bread...the thing is that I only fully enjoy the first few bites and then, it's not good enough.