Fasting Headache – Causes and Prevention

Skipping meals, rigorous dieting, and taking meals at longer intervals can all cause fasting headache and if not, they do put you at a higher risk of developing a headache. The pain is felt mostly in the forehead. Most people who choose Intermittent fasting to lose weight tend to get frequent headaches. The fasting headache usually begins after 14 to 16 hours of fasting and lasts as long as 72 hours in most conditions.

Symptoms of fasting headache

  • Nausea
  • Dizziness
  • Tremors
  • Hunger pangs
  • Loss of coordination
  • State of confusion
  • Feeling agitated.
  • Low mood and energy levels

The pain in fasting headache is non-pulsating and dull in character and mild to moderate in intensity

Causes of fasting headache

There are no known causes of fasting headache but some studies suggest:

Hypoglycemia: As the body goes into fasting, the blood glucose levels drop too low with the passage of time. Some people eat food with high carbohydrate content before the fast begins giving a spike up to their blood-glucose levels when their body goes into fasting mode, a sharp decline in blood sugar levels might trigger a headache.

Cortisol: The drop in glucose levels results in excretion of stress hormones, such as cortisol, by the body resulting in headache.

Dehydration: The brain is mostly comprised of water. As the body goes into fasting, the brain detects the decreased supply of water and starts producing histamines in response. Histamines directly cause pain and thus a headache.

Caffeine withdrawal: Caffeine withdrawal during fasting can also cause a headache as the blood vessels tend to dilate, boosting blood flow towards the brain and cause a headache.

Fasting and migraines

Fasting is a common migraine trigger. People who frequently get migraine attacks might suffer from migraines if they stay hungry for long hours. They should avoid skipping meals or try eating in intervals.

Management of fasting headache


  • Consume more fats during the periods when you’re not fasting, to keep your energy levels up.
  • Stay hydrated, as dehydration might trigger a headache faster.
  • Try not to skip meals.
  • Try to consume a small amount of food if you start feeling hungry to avoid triggering a headache.
  • Take a meal with low sugar content before you begin fasting.

Home remedies

  • Use pink himalayan salt to get rid of a headache.
  • Take something sweet, rich in glucose to overcome the hypoglycemia that might be causing you a fasting headache.
  • Restrict your caffeine intake a month before you begin fasting.
  • If you have to fast for religious purposes, Try taking small meals and increasing the duration between your meals to prepare your body for fasting.


Over the counter analgesics: Acetaminophen, aspirin, ibuprofen can help.
Oral rehydration solution: Can overcome the electrolyte depletion very fast.

When to consult a doctor?

If your headache persists even after eating food and your symptoms are only aggregating, you should consult a physician. Also if you have to fast for religious purposes and headache is interfering in your rituals, consult a physician who might suggest some prophylactic treatment to avoid getting a headache.


Why do I get a headache every time I fast?

This can be due to a number of reasons, namely; hypoglycemia, caffeine Withdrawal, dehydration, and release of cortisol (stress hormone).

What can I do to prevent a fasting headache?

Consume more fats during the periods when you’re not fasting also take a meal with low sugar content before you begin fasting.

When would the fasting headache go away?

The headache usually goes away within half an hour of eating something as your blood sugar levels start coming back to normal. At most, it takes 72 hours for the headache to heal.

Why does the frequency of migraine attacks increase upon fasting?

Fasting is a major migraine trigger and can initiate an attack. Try eating the bite-sized amounts of food in between your meals to keep your blood sugar levels stable.

Last medically reviewed on October 20, 2022.