Hmm. Sugar is the biggie for me, but it depends on what it is in. My biggest weakness is doughnuts (or any pastries, like others have said). Anything super refined--cake, white bread products--are a big no-no. Whole grain bread isn't a problem. Also, I can eat dark chocolate without it spilling over into the rest of my diet. I love potatoes and tend to feel guilty eating them (esp fries) but I don't know if I would call that a "danger" food. I don't have any problems with milk or dairy products as long as they don't have sugar. Yogurt sweetened with sugar is not a good thing.