The whole "Supersize Me" thing was interesting. On the one hand, I think it was beneficial, in that it forced companies like McDonald's to become more transparent. And, honestly, I think McDonald's does a pretty good job of that now. You know exactly what you're getting.
And, really, that's all I expect from any fast food place. Consumers can ultimately decide not to eat there, so I really think they should be able to sell whatever crap they want, as long as they aren't hiding anything.
It really bothers me when people blame these companies for them being fat or having health problems. Even when they weren't completely transparent. I mean, was it not common knowledge 10-20 years ago that burgers and fries were by no means healthy food, even if you made them yourself? I've definitely always known it. McDonalds didn't need to put nutrition information on all their products for me to know that their burgers were full of fat and calories, and their fries were drenched with salt. And, speaking as someone who used to be pretty chunky, I would never, ever blame my decision to eat crap food on the company that produces it.
I'll eat at McDonalds, or any other fast food place. Arby's is my favorite. The local stores make some damn tasty burgers, though American locations I've been to have been disgusting. However, like any junk food that tastes good... I don't eat it with any regularity. Maybe 3-5 times a year, on average.