It has become much harder, in the past century, to tell where the garden leaves off and pure nature begins.

There are many people who don't do well on a vegetarian or vegan diet, that for them, meat is a very nutritious food. So, I'm not prepared to give up meat. I don't think we need to give up meat, but we certainly need to change the way we raise meat and diminish the amount of it in our diet.

Students are very engaged by the issues, and it's not surprising because food choices are one of the few powers a child has.

Very simply, we subsidize high-fructose corn syrup in this country, but not carrots. While the surgeon general is raising alarms over the epidemic of obesity, the president is signing farm bills designed to keep the river of cheap corn flowing, guaranteeing that the cheapest calories in the supermarket will continue to be the unhealthiest.

There are fundamental tensions between the biological reality of the planet and the economic reality. To some extent you can adapt the economy, create a new set of rules and incentives to send it down a better track, but finally people in the first world are going to have to consume a whole lot less.

The soybean itself is a notably inauspicious staple food; it contains a whole assortment of "antinutrients" - compounds that actually block the body's absorption of vitamins and minerals, interfere with the hormonal system, and prevent the body from breaking down the proteins of the soy itself.

People have traditionally turned to ritual to help them frame and acknowledge and ultimately even find joy in just such a paradox of being human - in the fact that so much of what we desire for our happiness and need for our survival comes at a heavy cost.