There’s only one thing that we have to do in life, and that is to die.

I was raised on a dairy farm and ate plenty of meat and eggs until about twenty years ago. I started doing nutritional research, and a decade pr so after that my family made some major dietary changes. I'm just paying attention to what the data are telling me: The scientific evidence came first.

The answer to the American health crisis is the food that each of us chooses to put in our mouths each day. It's as simple as that.

Nutrition is not a mathematical equation in which two plus two is four. The food we put in our mouths doesn't control our nutrition-not entirely. What our bodies do with that food does.

DURING THE PAST TWO TO THREE DECADES, we have acquired substantial evidence that most chronic diseases in America can be partially attributed to bad nutrition. Expert government panels have said it, the surgeon general has said it and academic scientists have said it. More people die because of the way they eat than by tobacco use, accidents or any other lifestyle or environmental factor.

One way to identify the optimal human diet, pretty obvious to all but fundamentalist reductionists, is to survey and compare populations as they already exist, and see what they eat and how healthy they are.

Let’s start with the most prominent ecological crisis of our time: global warming. When you look seriously at the numbers, you find that switching from a meat-based to a plant-based diet would do more to curb and reverse global warming than any other initiative.