It's a basic fact of life that any given person can have a different take on any given subject. And every person will usually try to twist the facts to back up their opinion. One of the main reasons I don't take many "studies" too seriously is because of this.
For instance, PETA doesn't want me to drink milk so they'll tout lots of studies that say milk causes everything from digestive problems to "autism and schizophrenia in children." But the people of The National Dairy Council® disagree so they quote studies that say that lowfat dairy products, including milk, can help lower cholesterol, control weight and reduce the risks of colon cancer. I look at it this way, I love milk and so I drink it... but usually only after noon because my body doesn't like dairy too early in the day.
It's the same thing w/the fast food debate... did you see Super Size Me? I think the movie brings up some very valid points about the nutritional value of McDonald's food and fast food in general. But at the same time, it is very clear to me that Morgan Spurlock has a definite agenda with the movie. I mean, if you eat 5,000+ calories of anything for 30 days in a row while avoiding all physical activity, you're going to do damage to your body. Of course he got sick (I'd like to see his follow up where he eats that much food on a vegan diet and doesn't gain a pound but I not holding my breath).
Now I'd like to interject a story of my own... when I was in high school, my friend and I ate at McDonald's everyday for 2 weeks straight. The effect on our health? I lost 6 pounds and my friend lost 5! But how can that be? Well, for starters, forget about super sizing... she and I both ate All American meals. A hamburger (or cheeseburger), small fries and small soda (Sprite for me back in those days). That comes to about 650 calories. I couldn't tell you what breakfast and dinner was but I can assure you I never skipped a meal in those days. So, that wasn't all we were eating or anything. I'm not saying I was the picture of good health back then (or now) just that maybe fast food really can be part of a balanced diet. Balanced being the key word. Still, I wouldn't recommend eating fast food more than once a week.
Anywho - this post has taken up enough of my time and I haven't even gotten to the links yet. Here is Morgan Spurlock's blog and here is a counter-opinion site: Morgan Spurlock Watch. I find them both interesting and thought you might, too.