Keto Headaches: Diet Hangovers or Serious Business?

Anybody who has gone on the keto diets will groan when you mention keto headaches. They’ll then tell you about the worst one they’ve ever had. They’re so common that most keto diet enthusiasts have their own keto headache horror story.

Why might the keto diet give you a headache?

There are a few reasons the keto diet can trigger headaches:

low blood sugar
dehydration
electrolyte imbalances
carb withdrawal
lifestyle reasons like irregular sleep patterns and overexercising

If you’ve not heard of the keto diet what’s below may not make much sense to you. The simple keto explanation is that you replace carbs with healthy fats. This changes how your bod uses energy.

What are keto headaches? Why do you get them? How do you make them go away? Where in the world is Carmen Sandiego? We’ll answer three of those questions for you in this article.

person coping with keto headache header — Stanislaw Pytel/Getty Images

Why do low carb diets give you headaches?

Keto diets trigger a process in your body called ketosis, hence the snappy name.

Ketosis is a state your body can enter, like Florida — and you should always exercise caution when going into either. When there aren’t enough carbs knocking about in the bloodstream to draw energy from, your body starts to break down stored fat reserves instead.

The keto diet has a bunch of potential benefits, but also some risks. Keto headaches are a side effect of ketosis. The problem with ketosis is that many cells and organs in the body enjoy carbs quite a lot.

Replacing blood sugar energy with fat power can be a bit like putting diesel in a petrol engine. Except instead of your car blowing up on the middle of the freeway, you get a really bad headache that can last for 7+ days.

Are keto headaches symptom of keto flu?

Keto flu is an odd one. There’s no solid scientific explanation for it, yet (as anyone who’s experienced it will tell you) it very real and not very f*cking nice.

As the name suggests, keto flu is a whole mess of flu-like symptoms that show up to punch you right in your life because you dared to try and cut down your carb intake.

Keto headaches are common symptoms of keto flu.

What other symptoms come with a keto headache?

There are many other crappy symptoms of keto flu that team up with keto headaches to make your life keto miserable.

If you’ve just started a keto diet and have a headache alongside any of the following symptoms, there’s a good chance you got yourself a good old fashioned keto headache there, Jack:

digestive troubles like nausea, vomiting, constipation, diarrhea, and stomach pain
irritability
weakness or fatigue
struggling to focus
muscle cramps or soreness
sleeping problems
sugar cravings
dizziness

The intensity and combination of keto flu symptoms vary from person to person. There’s no way to tell prior to starting the diet how (or if) it will affect you.

A 2020 review found that most people report a keto headache and accompanying symptoms as starting within the first week of the diet. This sh*tshow normally lasts up to a week, although some report experiencing symptoms much longer than this.

What happens to your body when you start a keto diet

The whole point of the keto diet is to hack your bod into a state of ketosis. This means cutting out as many carbs as possible so your body burns off stored fat for energy instead.

Your body makes some X-Men level adaptations to a sudden drop in carbs. Your liver starts producing ketones to create an alternative source of energy for your brain and other vital organs.

Ketones are a chemical that come from the breakdown of fat. If ketones are a-lurkin’, it means your fats a-burnin’.

But ketosis comes with a lot of side effects. It’s not a small change, but a drastic shift in how your body produces energy. A significant drop in insulin levels often accompanies ketosis.

These big changes are why you can feel super weird when starting a keto diet.

Treating a keto headache

Praise the keto gods, for there are many ways to get keto relief from a keto headache.

Treatments are pretty simple. Unfortunately, there’s no guarantee that any of them will work unless you stop the keto diet completely. That doesn’t mean these treatments won’t work, but there isn’t solid scientific consensus about how effective they are.

Purely anecdotally though, any of the following are worth a try if you’re experiencing a keto headache:

Rehydrate. You lose a lot of water when you start a keto diet. A keto headache could be a sign you’re dehydrated. Drinking some water could do the trick. Hail Hydra(tion).
Cut down on booze. Alcohol also dehydrates you. Reducing your alcohol intake reduces risk of dehydration and the headaches that come with it.
Eat more water-rich, low carb foods. Getting some water-rich fruits and veg in your foodhole is good for a keto headache. Celery, cabbage, cucumbers, and raw tomatoes might work. Basically, if it’s a plant that goes squish when you hit it with a hammer, you’re good to go.
Eat more electrolyte-rich foods. The keto diet increases your risk of electrolyte imbalances, like a lack of sodium or potassium in the bloodstream. Some keto-friendly electrolyte bites include spinach, mushrooms, tomatoes, kale, pumpkin seeds, and the humble avocado.
Salt your food. Sodium gets a bad rap. Yes, too much salt in your diet is bad for you. However, no salt in your diet is also really bad for you. Salting your food a bit more could help balance your electrolytes and reduce your keto headache.
Take an electrolyte supplement. Electrolytes = good. Keto diet = electrolyte imbalance. Electrolyte imbalance = headache. Getting more electrolytes = headache go bye-bye.
Take it easy on the exercise. Entering a state of ketosis is a shock for your body. It needs time to adapt. Avoid putting extra stress on it during the start of your keto diet. If you push yourself too hard, the added strain can definitely be a headache-starting problem.

Is there a cure for keto headaches?

It depends what you mean by cure.

If you mean “is there a guaranteed way to stop a keto headache?” then the answer is yes. It’s called stopping the keto diet.

Keto headaches and keto flu are commonplace. A mild keto headache probably isn’t a sign of anything too serious. However, if the pain is unbearable or debilitating then you should absolutely put the diet on pause until you’ve spoken to your doc.

The keto diet is incredibly risky. You should always consult your doc or a nutritionist before trying one. If you stop and your keto headache continues, seek medical attention. It could be a sign of a more serious underlying health condition.

If your definition of cure is “a magic pill I can take that will make my keto headache go away while I continue not to eat carbs” then no. There is no cure.

Preventing a keto headache

You can minimize your risk of getting a keto headache with relatively little hassle.

Preventing a keto headache involves doing pretty much everything you’d do to treat a keto headache but before you’ve got the keto headache. Keto simple, right?

You can prevent keto headaches by making sure you compensate for the lost water and electrolytes in your body. Stay hydrated. Keep your electrolytes up. That’s the keto way.

Other keto diet risks

Keto headaches and flu aren’t the only side effects of ketogenic and other low carb diets. Here are some of the other risks that come with drastically lowering your carb intake:

Kidney stress

A lot of the high fat animal foods like eggs and cheese that are keto diet favorites also increase urine acidity. In children following the keto diet to treat epilepsy, this acidity can lead to excess calcium in the bloodstream.

This settles in the kidneys and forms kidney stones (or as urologists refer to them, pee-pee pearls). It’s worth noting that other factors may be at play in kidney stone formation, including dehydration.

Digestive issues and changes to gut bacteria

Carbs are a good source of fiber, so cutting them drops your fiber intake. This can make you constipated, which isn’t fun.

Changes to gut bacteria

There’s also some evidence to suggest that keto dieting messes with the good bacteria in your gut, although this is contested.

Nutrient deficiencies

Cutting out carbs doesn’t just mean putting down the burgers and Twinkies. You’re also saying no to a lot of fruits, grains, and legumes (like beans).

Depriving yourself of them can lead to serious nutrient deficiencies. Some key nutrients to be aware of here are potassium, sodium, magnesium, calcium, omega-3 fatty acids, fiber, and vitamins B, C, D, and E.

Dangerously low blood sugar levels

Peeps with type 1 diabetes on low carb diets are at a significantly higher risk of hypoglycemia (low blood sugar episodes). The keto diet is good for lowering blood sugar — but sometimes too good.

Bad bone health

There’s evidence that keto diets could have links to poor bone health. This is probably due to decreases in bone mineral density as your body enters ketosis. Further study is needed though, as the results are inconclusive.

Increased risk of chronic diseases and early death (maybe)

Firstly, that statement is a little dramatic and we’d like to point out that we’re not saying the keto diet will kill you. However, there is evidence that long-term low carb diets high in animal protein can be linked to higher rates of heart disease and cancer.

(The research also noted that low carb diets higher in veg actually reduced mortality. So it’s not all bad.)

As with most keto risks, more research is needed though. To avoid any doubt, don’t follow a low carb diet for long periods.

When to see a doctor about keto headaches

Keto headaches are common for peeps starting a keto diet. That doesn’t mean you should ignore them though.

Keto headaches (and keto flu in general) tend to start in the first week or so of the diet. They usually last no longer than a week. Symptoms tend to range from uncomfortable to very unpleasant, but not debilitating.

Speak to your doc if:

You develop intense keto flu later in the diet.
The headache lasts for longer than a week.
The intensity is such that you can’t go about your daily life.

It could be a sign that your body is reacting adversely to the diet or that you’ve developed a much more serious medical condition (like ketoacidosis, which is potentially life-threatening).