Preventing headaches and light-headedness when fasting

Prevent fasting headaches & light-headedness

During your first fasts it is not uncommon to experience headaches, light-headedness or dizziness. Our tips below may help you find the cause of your fast day headaches and how to help prevent them while fasting.


Drink plenty

We obtain a lot of water from the food we eat, so if you are not eating you do need to ensure you are drinking enough. We also lose more water than normal when we fast, for several reasons. Dehydration during fasting may be why some people experience headaches. If you don’t like water, you can have any no or very low calorie drinks like tea or coffee (you can include a splash of milk with your tea/coffee without ‘breaking your fast’), or miso soup.

Have a salty drink

Another reason for feeling unwell when fasting is because we are not taking in any salt when we fast and we may well be losing salt. As well as drinking plenty of no-calorie drinks like water, tea or coffee (you can include a splash of milk with your tea/coffee without ‘breaking your fast’), a salty drink such as vegetable, chicken or beef stock or bouillon, miso soup, or a vegemite or marmite drink can work wonders. Taken at around lunchtime or mid afternoon, a hot, salty drink can really take hunger pangs away and give you new energy and enthusiasm. Many new fasters find this an odd recommendation, but once they try it, they are convinced!

Don’t cut down on caffeine

If it sounds odd that we recommend drinking tea and coffee as normal, consider that caffeine withdrawal can cause headaches. One reason some people experience headaches when fasting is because they have stopped drinking their normal amounts of tea or coffee. Avoid having very milky coffee though as you will need to include the calories in the milk in your calorie allowance – keep it to a splash of milk (or none) and you will have more calories to spare for food!

Take pain-killers for your headache

If you do get a headache on your first fast(s), it is perfectly OK to take a pain-killer. Ideally this should be acetaminophen (paracetamol) rather than aspirin (acetylsalicylic acid) or ibuprofen based pain-killers. With more fasting you will quickly stop getting headaches, so there is no need to worry about having to take a pain-killer during your first few fasts if this helps you to feel better.

Visit the FastDay Forum for encouragement and inspiration

If you are feeling low, worried about something or just want to chat, you’ll find plenty of support and encouragement at the FastDay Forum. There is always a ‘Fasting today’ thread where you can chat with other people who are currently fasting, plus there are dedicated threads for different types of intermittent fasting.

Visit the FastDay Forum

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