800 or 600 calories for 5:2?

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800 or 600 calories for 5:2?

This topic contains 4 replies, has 3 voices, and was last updated by  Cinque 1 year, 2 months ago.

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  • Hi,

    I’m a bit confused – I read on one of Micheal’s posts that you can now have 800 calories on a fast day. Have I got that right? It’s just that I’ve been doing that but only lost 1lbs in 3 weeks!



    Hi Rob,
    Dr Mosley originally made the fast days 500 calories for women and 600 calories for men as it is a quarter of the average recommended daily intake.
    This was the MAXIMUM intake for fast days, many people do no calories or as little as they can sustainably manage (I do about 350 on average).

    Because so many people found this amount too difficult, and there was more research out, Dr Mosley found that the maximum could be upped to 800 on fast days and the 5:2 way of eating would still work. This makes it workable for a larger number of people.

    So it is up to you. The less calories you eat on a fast day, the more quickly you will lose weight. But the important thing about 5:2 is for it to be a sustainable, long term way of eating. Therefore, you might like to start with 800, and then as you get comfortable, find out the amount that suits your lifestyle etc.

    Good luck with it!

    Bethell: it is well worth reading Dr Mosley’s latest book ‘The Fast 800’. His guidelines cover more than just calories. There is a new cookbook due out in a week or so.

    Thanks so much Cinque, that’s really helpful. I’ll try eating a little less calories on fasting days and see what happens.

    Thanks Firefox7275, I we keep an eye out for the book.

    All the best,


    Cheers Rob, you’ll find what suits you. Somewhere in between 800 calories and water only! 🙂

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