The Fast Diet (also known as The 5:2 Diet) means five days of normal eating and two days of semi-fasting. We say semi-fasting because even on fast days you are allowed 500 calories for women or 600 calories for men.
The Fast Diet was created in 2012 by UK television presenter, Dr Michael Mosley, who investigated fasting as a way to improve his own health and hopefully to lose weight too. He interviewed scientists around the world who are studying fasting and came up with a method he felt would be easy to follow and sustainable. We think he succeeded! Together with Mimi Spencer, Dr Mosley wrote The Fast Diet book which was published in early 2013 and remained top of the Amazon best seller list for most of the year. It has now sold more than a million copies worldwide.
Dr Mosley settled on fasting two days per week, even though this has not been the subject of scientific studies (most studies so far have used fasting every other day), because he felt it was easy to do, and was enough to give gradual weight loss. Above all, he felt this method of fasting would be sustainable. He could see himself being able to carry on this Way of Eating for the rest of his life. By contrast, some of the fasting methods used in scientific studies were, he felt, not sustainable in the long term. And he knew, of course, that any weight loss would be only temporary if the new Way of Eating could not be continued into the maintenance phase.
5:2 is the method used by most of our community members. The speed of weight loss is quite variable but averages 1lb (0.45kg) per week. Read about our forum members’ Inspirational Weight Loss Stories.
How do I do it?
Fast days: on two days a week (preferably not consecutive days), eat just 500 calories if you’re a woman or 600 calories if you’re a man. You can divide up your calories into mini-meals or have just one meal – whatever suits you.
Non-fast days: eat whatever you like, in normal, sensible amounts.
FastDay says: It really is that simple! Although there are no rigorous scientific studies on 5:2 as yet, its sustainability and the fact that people who have tried it have lost weight and improved their health, makes it a great choice.
Why I like 5:2
Forum member Sallyo says “I do 5:2 because I can. It’s straight forward and easy now that I have learned what 500 calories amounts to. Other days I enjoy food, eat whatever I like. I love food. On 5:2 I don’t feel deprived at all and I haven’t changed anything about how I eat except on 2 days a week. I am strict on those days and don’t enter any deals or negotiations with myself. It’s a fast day so it’s off the menu unless it’s in the plan.”