Little wonder that it can seem unthinkable to say "no, thanks" to the modern-day equivalent of our tribe - our fear-driven culture.

In the late 1960s, there were alarming predictions that worldwide famine was around the corner. I wondered if humans had already lost the race, overrun the Earth's capacity. I let one question lead to the next, and unearthed information that would forever change my life: Not only is there enough food in the world to feed every man, woman, and child on Earth, there is enough to make us all chubby.

I think that fear of embarrassment is the essence of the human challenge.

My children threw me a life line: "Return to your roots - food - and rewrite your first book, Diet for a Small Planet." I learned that if I could just show up, in this case, if I could just get myself out of bed, get to the computer in my tiny office at MIT, and start writing, help would start arriving.

much agricultural land which might be growing food is being used instead to 'grow' money (in the form of coffee, tea, etc.).

My path has not been smooth. But the great thing about getting to be an elder is that you can look back and see the intense times of confusion and challenge, and see that if you keep walking through them, they can lead to times of great satisfaction and reward.

If we start with "limits" and a premise of scarcity and fear, it makes us fearful of each other, and that makes us vulnerable to anti-democratic systems.