Lots of people get headaches on fast days, and often it is due to cutting out something they usually start the day with, and that is caffeine.

Oh, and I sometimes dunk a dry water biscuit/cracker & have it with the Bovril. Certainly helps the headache & gets rid of the “sick” feeling I sometimes get.

I’d forgotten about salt. I don’t eat much in the way of processed food and probably eat less salt than the majority so didn’t give it a thought.
I rarely get headaches.

Hi Sissy65, I’m only in my second week so not much experience yet but during my first fast I got cold and headachy so started drinking my water hot, lots of it. Since then, 6 fasts later I’ve had no headaches. I’m in UK where its cold so hot drinks lovely, where are you? If you’re in Australia you probably won’t fancy hot drinks at the moment.

Hi JB20,

I wouldn’t be drinking a zero calorie sport drink!! It will have artificial sweeteners in it. Your brain will register the sweetness and anticipate a glucose hit. When the glucose doesn’t come the brain will be going WTF?? It will be craving the glucose hit it thought it was going to get. This is going to make life difficult for you. Go for plain water or carbonated water with a bit of lemon juice.

The headaches are a lack of glucose getting to the brain because your glucose levels will have dropped on the fast days. The headaches tend to go away or at least become less severe the longer you do the 5:2 diet. Your body becomes more efficient at converting stored fat to glucose. Initially I couldn’t go for my bike rides when fasting but now find it easy. Body is really cranking the handle converting fat to glucose when it knows its not getting any food intake.

I’m getting headaches frequently at about 1-2am during a fast.
Thinking about it, I probably drink less water in the afternoon (intentional, as I use public transport to get home from work) and evening, so need to up my water intake when I get home.
Paracetamol doesn’t usually help, but oddly, today after popping some pills at 2am I am fairly buzzing from feeling healthy and possibly a 7 mile walk to work 🙂
I’ve tried eating at 2am to try and cancel a headache – making it a 30 hour fast, but hardly ever works. Today I am trying to get to lunchtime with a 40 hour fast – was expecting to be really headachy, but feeling very good – still, there’s 3 hour 16 minutes to go, approximately, so anything could happen.

Could be lots of things:
1. Not enough water. Along with your “normal” water intake of 8 cups a day you have to add an additional 2-4 litres. This depends on your body size. Large body more water.
2. If you normally have caffeine, this could be caffeine withdrawal
3. If you eat high carbs and sugars you could be hitting a wall there.
4. Salt as you’re not taking salts in your food you’re not retaining as much water. Drink more water. DON”T take more salt. You want the water to flush your system. Kidneys, liver, bladder and bowels.
5. If the above don’t slow it or hopefully stop it. Take magnesium, calcium and vitamin D3.It is the last choice I’d do.

I think if you double or triple your water intake on fast days and up it as well on NFD your headaches will disappear.

When I started extended fasting I’d get a headache that would lay me out in a dark room on day 3-4. 4 Litres more of water a day was the answer for me.

A mild headache while fasting 5:2 is my body warning me to drink water. If I drink a litre at the first sign of a headache and then at least 300ml an hour I can tame them or kill them completely. This usually starts around 2pm. By 10 when I go to bed I will have consumed an addition 3.5 – 5 litres depending on how I’ve been feeling.

Stop 2 hours before bed and/or salty snack before bed. Sleep is important and getting up 3 – 6 times a night isn’t desirable.

I sleep 8 – 9 hours without having to get up. Of course I have to go BAD when I do wake up. I don’t drink much water after 8pm. But up until then I drink a lot. Both on FD and NFD I consume more water than a “normal” person does. I’ve had kidney stones removed twice. Dr. “It looks like a gravel pit in there!” Lots of water is part of my solution. Kidney stones are so painful!

Fasting and sleep pattern changes are very common. Some people will suffer from insomnia and only be able to cat nap.

On normal 5:2 fasting (water fast only) I do tend to wake up an hour earlier. I sleep pretty deeply and well and being is great because I love alone time in the morning. I can go for a walk, read, go for a drive, clean house, do laundry etc. My daily chores can be pretty much done by the time the wife and child get up. I can’t run the vacuum though they put their foot down at that.

On extended fasts over 3 days I sleep I mean it’s true sleep like I don’t get at any other time deep full and I don’t even move all night. I wake up just totally recharged. It’s a rejuvenation sleep and it’s totally amazing. It’s like the sleep of the innocent as my great grandma used to say. Though she’d look at kids sleeping say that and then add and they’ll be hellions when they wake too.

I do think that it is a mental thing how you can beat that low level aware sleep pattern I don’t know. I’m sure it’s a vestige hangover from prehistoric times.