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.

I was aware of what animals go through because I had driven animals to slaughter and I'd killed animals. And I was aware that there were certain ethical issues, but they weren't preying on my mind very heavily.

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 thinnest people on the planet are those who eat the most carbohydrates.

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.

Overall, our population is in the worst shape it's ever been. Children are in terrible shape. We have absolutely unprecedented numbers of obese and overweight children - one in three now. A generation ago it was something like one in ten.

In my own life, I decided to leave meat off my plate in medical school, but was a bit slow to realise that dairy products and eggs are not health foods either.