Bonus: 'Fasting' featuring Dr. Jason Fung

When you look at what happens to the body during fasting, in fact, the body doesn't shut down; it actually revs itself up. It actually increases noradrenaline [and] increases growth hormone. So, because you're increasing your sort of fight-or-flight response, which is your sympathetic tone, you're actually more focused. You're actually going to be able to concentrate better.

There's a list of carcinogens that the World Health Organization maintains, but when you look at, in a population, how much it contributes to cancer overall, it tends to be sort of like 1%, 2%, 3%—which together can be important, but obesity and diet and so on tend to be the biggest part.

In diabetics, metformin seems to reduce the risk of certain types of cancer—breast cancer, particularly.