You could have two completely different careers if you could stay healthy to 90. How fascinating that would be.

Carbohydrates, and especially refined ones like sugar, make you produce lots of extra insulin. I've been keeping my intake really low ever since I discovered this. I've cut out all starch such as potatoes, noodles, rice, bread and pasta.

A big tree seemed even more beautiful to me when I imagined thousands of tiny photosynthesis machines inside every leaf. So I went to MIT and worked on bacteria because that's where people knew the most about these switches, how to control the genetics.

It was like stepping on to an escalator; I could do anything. I was just made for science.

If I were a worm, I would rather be the long-lived mutant than the normal worm, that's for sure.

The idea that ageing was subject to control was completely unexpected.

Ageing is very exciting. But if I didn't work on ageing, I'd want to work on the brain. There are really cool techniques you can use now. And bioinformatics. The methods you can use for comparing large data sets - that's so powerful.