What is intermittent fasting?

Intermittent fasting is classed as a diet, but is, more accurately, an eating pattern, comprising of periods of fasting and periods of eating ad libitum (“at one’s pleasure”).

There are three main fasting methods:

• 16/8 method (time-restricted feeding). People who follow this approach fast for 16 hours and eat for 8 hours. In fact, whilst 16 hours is suggested, those who do time-restricted feeding fast for anything from 12 to 21 hours. It is the most popular form of intermittent fasting.
• Eat-stop-eat (alternate day fasting). This concept involves fasting for 24 hour periods, once or twice a week. Although participants can eat what they like on the non-fast days, studies suggest that most people naturally reduce their calorie intake on the days in between.
• 5:2 diet (modified fasting). Those who adopt this approach reduce their energy intake by 70-75% for two non-consecutive days each week. On the fasting days they limit themselves to between 500 and 600 calories, eating ad libitum on the remaining days.