I do believe from Good Calories, Bad Calories that ultimately what is bad for you is grains and sugar. That protein, and fat is great for your body. The Paleo diet is a form of that diet, except it's hunter/gatherer. So you're encouraged to eats lots of veggies, meat, berries and nuts and in moderation: fruit, and tubers. I think really strict paleo cuts dairy.
Anyways, so he inspired me to try this, and right now I'm flirting with it on and off, but after the holidays I would like to do it more strictly. I tried it just for one day, and had so much energy, physically and mentally. I started doing a lot of stuff for work that I've been putting off. And today, I had rice and sugar (in the form of hazelnut chocolate) and now I feel bloated and sluggish and lazy and unmotivated. I'm definitely going to play with it more.