Headaches are killing me on the 5:2!!!

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Headaches are killing me on the 5:2!!!

This topic contains 4 replies, has 3 voices, and was last updated by  Firefox7275 4 years, 8 months ago.

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  • Hi i have been doing 5:2 for a few months now but the headaches are killing me on fast days. i thought this will subside once my body gets used to it once it learns using ketones as fuel instead of glucose but it didn’t! i take breakfast first thing on fast days, an apple midday and dinner which makes a total of 600K. i make sure i drink water throughout the day (2 liters), coffee ( i always drink decaff coffee) and tea but nothing seem to help. I dont have diabetes or high blood pressure or any other serious health issue.
    any advice?


    I drink at least 2 litres of water plus teas and coffees on non fast days. We get most of the water we need from our food so you could try increasing the amount you drink on FDs.
    I always find that something salty helps with headaches, a cup of instant miso soup, clear broth or even a couple of pinches of salt and a glass of water.

    Hope this helps.

    My first suggestion is go back to basics: read whichever of Dr Mosley’s books you have again, double check you are following all of the guidelines and troubleshooting. There is so much information it is easy to forget some.

    What time of day your headaches begin relative to your eating schedule and activity schedule may give you more clues.

    Are you tracking what you are eating on both Fast days and non-Fat days? You do not say what your breakfast or dinner are, but a whole apple is high in sugar so vegetables are preferred (p.93).

    Without protein (p.92) or fat to slow to slow your digestion, the fruit may cause your blood glucose to peak and trough. Without mineral-rich foods or rehydration salts you may be low on electrolytes/ body salts (p.138).

    In brackets are the page numbers in the latest of Dr Mosley’s books (The Fast 800).


    1-headaches begin at 10.30 am till dinner at around 6.30 pm
    2-i am tracking fast days only
    3-fast days plan is fixed. one boiled egg with green salad 6.00 am + black decaf espresso, red apple at 12.00 midday, low cal spray fat fried sea bass piece with vegetables and strawberry at night with decaff coffee, water and herbal tea throughout the day. i get 600k exactly on fast days!
    4-i know your point about the apple but that was what mimi rogers, mike coauthor, does and suggested
    5-i haven’t read the 800 book but read the 5:2 about 4 times now
    many thanks

    Useful information, thanks. Poor you, a headache all day is so wearing.

    So the lunchtime fruit is not the trigger, but it is not helping either. That fits with the possibility that your electrolytes/ body salts/ mineral balance is off and/ or you are dehydrating (may be linked).

    What helps our body hold water that we drink is food, especially starchy carbs and fibre, and electrolytes. Clearly we are not eating much starchy food on Fast days!

    I would suggest increasing mineral-rich foods (seeds/ nuts/ beans/ lentils/ unprocessed whole grains/ cocoa) on your non-Fast days. And increasing electrolytes (a little rehydration salts) the evening before and on the Fast day itself.

    Hopefully these fit with Dr Mosley’s ‘5:2 Diet’ book?

    If that doesn’t help, you might read some of the news articles online where Dr Mosley talks about 800 calorie Fast days. Many of these articles long predate the updated book, so are very much aimed at people who have been following the ‘Blood Sugar Diet’ or the ‘5:2 Fast Diet’ programme.

    I think ‘The Fast 800’ was partly intended to bring the different readers together. BUT many of us have now read a different combination of books to others on the forums …. I came from ‘Clever Guts Diet’ for example! Confusing.

    Hope you find a fix ASAP.

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