The Stone Age gave us arrow heads and eventually knives, and that allowed us to kill animals in ways you couldn't before, and once you had them you were able to remove the skin and bones.

I think we have to do everything that's useful. We're doctors. Our job is to tell the truth. And it doesn't have to be embellished in any way.

Chicken fat, beef fat, fish fat, fried foods - these are the foods that fuel our fat genes by giving them raw materials for building body fat.

Dogs have a sense of smell much greater than ours and they're much faster than we are. We have fairly dull senses, fairly slow locomotion. In our Olympic trials, we celebrate speeds that would be an embarrassment to a bird or a dog or another animal.

I am always struck by how difficult it is for people to see how much cruelty they are bringing not only upon animals but upon themselves and their loved ones and other people, how much we are screwing up the planet, how much we are hurting our own health, how hard it is to change all that, how eager people are to make a buck at everybody else's expense - all those things are discouraging.

The important thing is that while heroin and cocaine and tobacco and every drug and junk food cause dopamine release, there are healthier ways that you can put this into your life. And the three big ones are intimacy ... physical activity ... and the third thing is music.

The dangers of eating animal products occur after the age of reproduction. If people developed cardiovascular disease that was fatal by the age of twelve or thirteen, eating animals would have died out long ago. You get it after you've already reproduced.