I just saw a film I've heard about for years: Super Size Me. It's about a journalist/film maker who eats nothing but food from MacDonald's for an entire month. If a clerk asks if he wants to "super size" the meal, he says yes.
In the space of 30 days his body goes haywire, both physically and mentally. His liver begins to fail, his cholesterol shoots through the roof, he gains over 20 pounds. He is exhausted all the time. His mood starts to swing and he encounters bouts of depression. He then gets headaches if he doesn't eat more of the fast food.
This guy was extraordinarily healthy. He went and checked in with several physicians and nutritionists. He was normal weight and in extremely good health. His girlfriend was a vegan chef. Their normal diet was healthy to the max.
The change in this man's health amazed, depressed and disturbed me. Basically, he adopted the level of exercise most Americans get, and ate an exclusive diet of fast food. I'd recommend anyone who can see this film. You can get it for free on sites like hulu.com.
Amazing. Disturbing. Essential.