The founder of Bulletproof, a nutrition and supplements company, explains how regular intermittent fasting brings surprising benefits, sharing exactly how to go about it sustainably.

If you've ever questioned why three meals a day, every day, came to be the norm, you're not alone.

Intermittent fasting features in almost all religions and is known to bring benefits way beyond weight loss.

Self-styled 'seeker' Dave Asprey founded the Bulletproof business empire after long investigations into the spiritual and physical effects of controlling what we ingest.

Fast This Way starts with Asprey's shamanic 'vision quest' and goes on to show how central the practice of fasting has become to his sense of self.

Asprey's fasts aren't too strict: they involve vitamin supplements and regular hits of enhanced 'bulletproof' coffee.

Asprey encourages us to fast in a way that works for us, giving separate advice for women and men, and for different life stages, along with advice on how to avoid the 'fasting trap.'