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.

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 think herd mentality is a good thing overall. Because if every sheep had to figure out the velocity of the wolf and their personal risk, that would take forever.

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.

People have to know that if they've wanted to lose weight, if they've wanted to get their diabetes better and get their cholesterol down, here is how it works. Beyond that point, you can't force people into changes, you have to guide them.

I'm thinking of people in rural Japan and China, where McDonald's hasn't yet arrived. These are the thinnest, healthiest, longest-lived people with the least risk of cardiovascular disease and diabetes.

Another advantage of avoiding sodas is that you will avoid the caffeine that is in many of them. Caffeine is a weak diuretic that causes calcium loss via the kidneys.