"I think the most important thing is to keep active and to hope that your mind stays active." — Jane Goodall

I did this book 'Harvest for Hope,' and I learned so much about food. And one thing I learned is that we have the guts not of a carnivore, but of an herbivore. Herbivore guts are very long because they have to get the last bit of nutrition out of leaves and things.

It has actually been suggested that warfare may have been the principle evolutionary pressure that created the huge gap between the human brain and that of our closest living relatives, the anthropoid apes. Whole groups of hominids with inferior brains could not win wars and were therefore exterminated.

I'm highly political. I spend an awful lot of time in the U.S. trying to influence decision-makers. But I don't feel in tune with British politics.

We can't leave people in abject poverty, so we need to raise the standard of living for 80% of the world's people, while bringing it down considerably for the 20% who are destroying our natural resources.