Endorsed by celebrities and chief executives, fasting was followed for cultural and religious reasons historically, but across the world it is gaining popularity as a “bio-hacking” health and weight-loss regime. Yet a systematic evaluation of 40 trials concluded that intermittent fasting works, with a typical weight loss of three to five kilograms over 10 weeks.

Intermittent fasting is free, and part of its appeal is that it is simple to follow. It works by focusing on when you eat, rather than what you eat, within a restricted time window.

The Telegraph London