I felt so bad for his girlfriend, the vegan chef! Although I guess, now that it is over, she is probably happy with the impact it has made.
Of course I felt bad for him too! For one thing, I imagine his caffeine/sugar withdrawal was a total nightmare!
I agree with Lindsay that probably the most powerful part of the film for me was how inaccurately the doctors predicted the consequences of the diet - they only predicted increased blood cholesterol and weight gain (if I remember correctly). While he did gain weight fairly fast, it seemed obvious to me that the significant damage was INTERNAL and thus out of sight. I don't think we realize what we do to our body when we eat highly processed, low quality food. If we're not gaining too much weight then we figure everything is okay and we're healthy.
What really bothers me is that is it CHEAPER to eat a crappy, processed and unhealthy diet in the United States than it is to eat healthful, varied diet. One way to indirectly improve our healthcare system would be to find some way to address this problem. I realize it is very complicated and is hard to address without taking away some freedoms, but I still wish I could be addressed somehow!