Let us also be frank here folks. Virtually everything is bad for you, and if you look into any subject matter too much, it will break your heart. Dangerously Delicious is more clued up than most in this area, as most veggies are. They are aware of all the terrible practices, that the rest of us let slide, or just don't care about. But you can apply that level of research to anything, and be left in despair about the legacy of the human race. From endangered species, rainforests, and Chinese medicine to how they want to get more fossil fuels out of the earth, to how they make a 12 year old kid make your £100 Nike for 50p a week. There is so much wrong with everything humanity does, that to look too closely at any single aspect is not good for anyone with a conscience.
His ex-wife Alexandra Jamieson who is in that film is a chef and 'holistic health counselor' apparently (don't know what the second of those things is) so she was in charge of his prior and recovery diets I think. I viewed that film as like a controlled experiment only in the real world, not a lab. Eating a perfect diet is pretty much impossible for most people. Some people are more committed to eating healthy, not eating meat, being a foodie than others. I do often wonder what would happen if I ate meat again, don't know what the effect would be tbh, but I think you're right in that changing your diet in such an extreme way is going to produce an adverse reaction. But, he's a film maker creating an entertainment product and needs controversy and excitement to get people to go and see his films. In a way he's as implicated in the practices of McDonalds that he criticises by using the company as a tool to make a film.