fast food industry, is it making americans fat?

Everyone loves the Big Mac, the Whopper, a chicken sandwich, or a spicy burrito.  These things are delicious and we all know it, but what kind of health risks are there when these things become a main choice of our daily diet?  A recent documentary called "Super Size Me" shows the effects of fast food diets and how they can effect your health.  It is about a man who strictly eats only McDonald's food for every meal he has, no salads, just the menu from McDonald's.  Throughout the documentary you can see the health risks that he gains just from dieting for one month on only fast food.  As a research topic I would like to introduce this dilemma as my topic for discussion.  I truly believe that fast food corporations are the main contributor to the increase in obesity of Americans .  I am looking forward to finding out more information and supporting my argument.