How it works

Example: to avoid jet lag on a trip from London to New York, begin the diet three days before the day of the flight. The first day is a feast day, followed by a fast day. The day of the flight is always a fast day. Coffee should only ever be taken between 3pm and 5pm

Feast days: eat three full meals. Take second helpings. Breakfast and lunch should be high in protein, which helps the body produce chemicals to wake up and get going

Fast days: eat three small meals. They should be low in carbohydrates and calories to help deplete the liver's store of carbohydrates (small salads, thin soups and half-slices of bread)

Flight day: sleep as soon as possible on the plane, then begin a feast day in New York