Yesterday was my first day of Keto Diet.

I started experiencing headache in the evening. Was it due to me being on Keto?

  • I've heard others talk about "keto flu" where you essentially get flu like symptoms when you first go into keto (or back out of it). I think there are also mineral deficiencies that can occur as part of a ketogentic diet. Have a look at reddit.com/r/keto you may find more information (or a better answer) there
    – Dark Hippo
    Mar 21, 2017 at 9:41

1 Answer 1


Experiencing headaches on Keto diets in normal. It usually happens after 2-3 days.

Two mains reasons for this:

I Your brain normally functions on glucose. When glucose is missing, your liver starts producing ketones. These are the only substitute your brain can use to get energy. However it can take some time for them to be produced. During that time your brain will not have enough energy and fogginess/headaches can occur. You will get passed it once your liver starts producing enough ketones.

According to the ketogenic diet by Lyle McDonald, your brain can only get around 75% of its energy from ketones. Make sure you still get some carbs.

II Keto diets can be high in sodium. A high sodium intake results in dehydration (sodium being a diuretic). Mild headaches are usually caused by dehydration. Make sure you drink more water to avoid that common side effect.

I hope this helps !

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