Everything You Need to Know about Keto Headaches

The Keto diet is great for losing weight, regulating blood pressure and increasing your energy levels.  However, if you’re thinking of beginning Keto you might have heard that it causes headaches.  This isn’t entirely true and if you follow the rules of keto you shouldn’t have to worry about headaches.  The following article will explain when you might get headaches on Keto and what you can do to treat them and prevent them so that you can enjoy all of the many benefits that Keto has to offer. 

Keto Flu

The main reason that people get headaches on Keto is due to the Keto flu.  The Keto flu is a brief period when you begin Keto where your body is adjusting to the switch from glucose to ketones.  It usually lasts anywhere from 2-4 weeks for most people. 

The symptoms are similar to what you’d experience with a real flu.  You might feel draggy and tired.  Your brain might feel foggy and you might have trouble concentrating.  You’ll often feel muscle aches and stomach issues such as nausea.  Lastly, you’ll probably get headaches. 

It’s important to note that these symptoms are completely normal.  It’s part of the process where your body adjusts to using ketones as fuel and your symptoms should go away within a month.  You can think of the Keto flu as being similar to the withdrawal process for someone coming off of drugs and alcohol.  Your body likes the way that carbohydrates make it feel and it’ll resent the change a little bit. 

However, once the switch has been made, you’ll feel fantastic!  Your energy levels will improve, you’ll have increased mental clarity and you’ll sleep better at night.  You’ll no longer experience frequent hunger cravings and your weight will most likely drop.  It’s worth sticking it out through the Keto flu in order to get to the benefits.

In order to try and prevent or limit the stress on your body when beginning Keto, it’s best that you limit your carbs as much as possible right away.  Your natural instinct might be to wean yourself off of carbs slowly, but this can actually have the opposite effect that you intend, and you might find that your brain fog and headaches last longer.  Cutting back rapidly causes your body to burn through its available glycogen which forces your brain to begin using ketones faster than it would if you slowed the process down.  As soon as your body and brain have made the switch, you’ll feel a lot better.

Other Causes of Keto Headaches

Although the Keto flu is the most common cause of headaches while on Keto, there are some other causes that you might want to be aware of. 

If you’re experiencing headaches on Keto you should first ask yourself how much water you’re drinking.  Dehydration is one of the leading causes of headaches whether you’re on Keto or some other meal plan.  It’s common for Keto beginners to experience dehydration because as you remove the carbs from your diet, your body slows down on its retention of water and begins flushing it out of your system.  This is why you might notice a lot of weight loss right at the beginning of Keto.  Although long-term Keto leads to real weight loss, Keto in the short term triggers your body to get rid of excess water and so the weight loss that you see is very likely water weight being shed.

The second reason that you may be having headaches on Keto is due to sugar withdrawal.  You’ve probably heard that sugar is addictive, and this has been shown to be scientifically true.  Like with most addictions, the more sugar your body has, the more it wants.  Sugar activates the reward centre in the brain which signals it to request (and crave) more and more sugar.  Although you may believe your current diet to be low in sugar, the truth is that if it’s high in carbs, it’s high in sugar.  As you remove this sugar from your diet through Keto, you’ll feel the physical effects of withdrawal that often include headaches.

Because your body sheds water during Keto it also gets rid of electrolytes. Having an electrolyte imbalance is a leading cause of headaches and it’s common in people new to Keto.  Electrolytes leave your system as they are flushed out with the water.  Sodium, potassium and magnesium are the three electrolytes that are most affected by the diuretic effect of Keto.

When your body is faced with an electrolyte imbalance it disrupts the flow of water into and out of your cells.  It also causes brain fog, headaches and problems regulating your body temperature.  Because your body flushes out so many electrolytes while on Keto this means that your electrolyte requirements are higher on Keto.  If you’re experiencing Keto headaches take a look at how much sodium, potassium and magnesium your body is getting.  You may have to increase your intake.

How to prevent Keto headaches

Preventing the headaches that come with the Keto flu requires you to dive into your Keto headfirst.  Slowly easing into the calorie restriction will probably just make symptoms such as headaches worse and draw the duration out longer.  Instead, restrict your net carbs to as few as you possibly can in the beginning.  You might be able to raise them closer to the 20-25g net carb limit after a few weeks. 

You might also want to eat more fats during this beginning phase of Keto.  If you supercharge the amount of fats that your body receives it will make it easier for it to make the metabolic switch from glucose to ketones.

After the first few weeks of your Keto are finished and you’ve made it past the Keto flu you need to keep a close eye on your electrolyte levels and your water intake.  There’s a good chance that you might need more of both now that you’re on Keto.  Getting enough electrolytes and water goes a long way towards preventing headaches on Keto.  You might want to consider having a teaspoon of salt and a glass of water.  Drinking this salt water will pump extra sodium into your body alongside the water which will help you raise both levels.

Sleep is also an important factor.  When you’re tired your body can’t perform at its peak.  This makes everything harder, increases your stress hormone cortisol and it can even contribute to headaches.  Make sure you’re getting enough sleep every night, especially in the beginning stages of Keto.  It’s a large adjustment for your body to make and adequate sleep can make the process a lot easier on you. 

Exercise can help your body increase its metabolic flexibility.  One of the reasons that you get a headache when you’re new to Keto is the difficulty and confusion that’s caused by your body making the switch from glucose to ketones.  An increase in metabolic flexibility can help make this switch easier for your body to make.   You’re not going to have a lot of extra energy when beginning Keto; however, if you try to move a little each day you’ll decrease the number of days that you experience side effects from the Keto flu.

Keto as a treatment for migraines?

Despite the headaches that often accompany the switch from a carb rich diet to one that’s fuelled by fats; there is some interesting studies being done into the use of the Keto diet as a treatment for migraines.  The studies have been small to this point, but the research looks promising.

One of the first studies was done back in 1928 and it showed that 39% of participants experienced a decrease in their migraine symptoms after following a Keto diet. A few years later, in 1930, another study was completed that showed that 28% of participants didn’t have a migraine attack for 3 months following the beginning of the Keto diet with another 25% noticing a reduction in their symptoms.

More recently, a study done back in 2015 showed that women who followed a Keto diet for at least a month saw a reduction in the number of migraine attacks that they experienced.  Because this could have been the result of weight loss instead of the Keto diet specifically, a follow up study was done by the same researchers that compared migraine frequency in those switching to a low-calorie diet compared to those following a low-calorie Keto diet.  The researchers found that those on Keto had 3 fewer migraines a month than those on the low-calorie diet alone.  This would point to Keto as being the helpful factor rather than weight loss alone.

This is good news for migraine sufferers; although, more research does need to be done.  If you suffer from migraines, you might want to talk with your doctor to see if a Keto diet might benefit you.


It’s common to experience a headache during the first few weeks of Keto as your body adjusts your metabolism to burn fat as fuel.  However, the side effects of the Keto flu can be limited by diving into your low-calorie diet quickly rather than drawing it out as well as increasing the amount of sleep, water and electrolytes that you get.  With proper management, the Keto diet shouldn’t cause long-term headaches in people; however, if you have any health concerns while in Keto remember to speak with your doctor to rule out any underlying conditions.

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