View the trailer!
Three rules:
1) No options: he could only eat what was available over the counter (water included!)
2) No supersizing unless offered
3) No excuses: he had to eat every item on the menu at least once
All in all a very enjoyable film. But I expected him to look physically worse at the end than he did. His annoucement that in one month he had eaten in fast food what the average nutritionalist says you should eat in 8 years comes as a shock! Morgan Spurlock comes across as an agreeable, humourous presenter in a film very much in the Michael Moor genre.
Interestingly, here's what McDonalds main website has to say:
"This movie is all about one individual’s decision to act irresponsibly by consuming more than 5,000 calories a day - - twice the recommended level for adult males - - and by purposely limiting his physical activity. That’s why this movie makes no contribution to the important dialogue taking place today on nutrition and balanced lifestyles. "
True, we don't see him walk far, although he travels the US by car. He's asked if he would like to 'super size' 5 times in Texas alone. And 85 branches of McDonalds in Manhatten alone?! :O
No wonder he's warned by his GP to stop the diet or risk his liver packing in with a week to go! And if you don't want to watch a stomach shrinking operation... avoid this film.

More McSpin...
"Customers in the U.S. can get comprehensive nutrition information through in-store brochures, McDonald’s website or a customer toll-free number."
Not from what we saw. Barely any branches had this information at all. One had it on the wall behind a display and another proudly on the wall... in the basement!
McDonalds even put out a disclaimer at the beginning of the film asking people to visit this website to read the truth.
From my experiences, I have found the fries less salty lately. That's if I have them at all, I often go for the side salad instead. And the chicken nuggets now contain '100% breast meat'. So what the hell was in them before? Chicken gonads?!

Be warned though, the chicken salad contains more fat than Big Mac!