2 Simple Ways to Avoid Fasting Headaches

Have you ever gotten a headache while fasting? Or perhaps you’ve heard of other people getting headaches while fasting, and wondered how to avoid them?

Today I’ll explain what causes fasting headaches, and what you can do to prevent them.

I’ll also explain two methods you can use to treat a headache if it starts during intermittent fasting.

Let’s get started.

How does Intermittent Fasting Cause Headaches?

There are two main reasons why you might get a headache while fasting.

1. Starting Too Quickly

When you first start intermittent fasting, a lot of changes happen in your body.

For example, various hormones are fluctuating, including insulin, cortisol, adrenaline, and others. 

Without getting into all the details, the bottom line is that a lot of things are moving around, and it’s likely different from what you’re used to. Which means you’ll also feel different, and may have some unexpected symptoms.

One of those symptoms may be a headache. 

(Side note: The changes I’ve described here are also related to the “keto flu”.)

2. Salt and Other Electrolytes

When you start fasting, your insulin level goes down. Lower insulin results in your kidneys releasing more salt (aka sodium) and water.

In other words, you’ll be losing more salt, water, and other electrolytes through urination.  As a result, you’ll have a lower sodium level in your bloodstream. You’ll likely also have lower levels of other minerals, such as potassium and magnesium.

Low levels of these minerals can cause cramping, dizziness, and a variety of other symptoms–including headaches.

How to Prevent Headaches while Fasting

Keeping in mind the above, there are two main steps for preventing headaches during intermittent fasting.

Step 1: Build Up Gradually

Since your body has a lot of adaptations to do when you start fasting, it’s best to build up a little bit at a time so you can get used to it. 

In other words, start with a super easy version of fasting, and progress one little baby step at a time.

Here’s a video where I explain one method for getting a smooth and easy start with fasting:

If you take the approach I describe there, you’ll already be doing a 12-hour overnight fast before long. Then you can gradually increase the duration of your overnight fast (while shortening the duration of your daily “eating window”), little by little.

Step 2: Boost Your Salt and Other Electrolytes

Since low electrolytes can contribute to fasting headaches, it follows that boosting your electrolytes can help prevent headaches while fasting.

The main electrolyte to focus on is sodium (aka salt),  because that’s the most plentiful one in your bloodstream, and the one that helps maintain your blood pressure.

For most people, a few extra grams of sodium per day will do the trick. (1 gram = 1,000 milligrams.)

Potassium and magnesium are the two other electrolytes that are often worth supplementing while fasting.

If you wanna get into the nitty gritty details about electrolytes, check out this podcast episode:

Episode 20: Salt & Electrolytes: Why you NEED Them, How to Get Them 

Caution:  There are some medical conditions where electrolyte supplementation needs to be done cautiously. Make sure you do adequate research and consult with your own medical providers.

How to Get Rid of Fasting Headaches (after they start)

If you’re fasting right now and you already have a headache, here are a few things you may want to try. 

You could start with a medication like Tylenol. But you may want to consider trying one of the other methods below, since they’re more likely to get at the root cause and hopefully eliminate your headache.

1. Take Some Electrolytes

We’ve already talked about this one. Not only do electrolytes help with prevention, sometimes they can help you get rid of a fasting headache as well.

Take some extra salt, potassium, and magnesium, and there’s a good chance you’ll start feeling better.

2. Use Training Wheels

If electrolytes don’t do the trick, you may also want to try using some “training wheels”.

Training wheels are little bits of food that don’t really disrupt your fast, but can help you feel better in a pinch.

For example, you could try a few olives, a couple tablespoons of chia seeds (soaked in water), or a glass of bone broth.

Just like when you learn to ride a bike, you don’t have to use training wheels forever. But when you’re a beginner, it helps you get a smoother start.

Of course, if you’ve tried these methods and you’re still not feeling well, it’s probably time to quit your fast. Furthermore, there’s always a chance that something more serious is going on, as opposed to just a benign side effect from fasting. So if in doubt, seek medical care.

Related Questions

Here are a few other questions related to fasting headaches.

Can Intermittent Fasting Cause Headaches?

Intermittent fasting can potentially cause a headache because of all the different changes happening in your body. That includes electrolyte and fluid shifts, as well as various hormone changes as I described above.

How Long Do Intermittent Fasting Headaches Last?

Like hunger pangs and other fasting side effects, fasting headaches may simply go away on their own in an hour or two. But it depends on what’s causing the headache.

In many cases, the headache will go away once you’ve addressed the root cause (e.g. a low sodium level).  

How to Avoid Hunger Headaches When Fasting?

“Hunger headaches” is probably a misnomer here. Most likely, it’s not hunger that’s causing a headache while fasting, but rather some electrolyte or hormone related changes.

In general, the way to avoid these types of fasting headaches is to build up gradually so your body has time to adapt, and to supplement your electrolytes.

Is it Normal to Have Headaches During Intermittent Fasting?

Yes, it can be perfectly normal to get a headache during intermittent fasting. But you can likely prevent them easing into things and giving your body a chance to adapt, boosting  electrolytes, or using training wheels.

Final Thoughts

Headaches are a somewhat common side effect of intermittent fasting.

In this post I explained a couple of the most common reasons for getting headaches while fasting, along with a couple ways that you can probably prevent fasting headaches.

I also explained what you can do after you develop a headache, to hopefully get rid of it.

For additional step-by-step guidance about how to get a smooth start with intermittent fasting, check out my podcast (details below)!