The keto diet has long been praised for accomplishing what many diets cannot.

These accomplishments include:

  • Improving brain function.
  • Providing your body with more energy.
  • Enabling you to achieve peak performance.
  • Weight loss [1].

Like all good things, however, it has its pitfalls as well.

One of the more common gripes people have with the ketogenic diet is the headaches and other unpleasant symptoms that often accompany the first few weeks. These unpleasant symptoms are commonly referred to as the keto flu.

While this can be an encumbrance, there are plenty of ways you can avoid the keto headache to ensure only smooth sailing on your carbless journey.

Body Changes on the Keto Diet

To understand why keto headaches occur, it’s important to also understand what’s happening to your body when switching to a low-carb, high-fat diet like the ketogenic diet.

Carbohydrates are a normal part of most people’s everyday diet, and our bodies and brains have learned to rely on these carbs as its primary source for fuel. So what happens when you transition to a diet very low in carbs and higher in fat?

In a nutshell, this creates a bit of metabolic “confusion,” as your body is adapting to using ketones from fats for energy instead of carbs (a.k.a glucose). This initial “induction phase” typically leads to some unpleasant flu-like symptoms—hence the term “keto flu”—such as brain fog and headaches.

Your body is going through a drastic metabolic shift and therefore experiencing physiological withdrawal from the lack of carbs.

When you start restricting your carb intake while simultaneously increasing your fats, your body will burn through its last stores of glycogen. This leads to brain fog and lack of focus since your brain doesn’t know where to pull energy from.

Stress on Your Body

Since there is no longer sugar from carbohydrates in your diet, your body will have lower blood sugar levels while also increasing in cortisol [3].

Cortisol is a stress hormone released by your adrenal glands to ensure your body has sufficient energy for survival.

Having low blood sugar levels indicates to your brain to send a signal to the adrenals to release cortisol. Cortisol may then signal the liver to initiate a process known as gluconeogenesis to help convert amino acids into glucose for energetic purposes.

However, so long as you’re consuming adequate fat, gluconeogenesis will remain negligible.

The important thing to remember is that your body will adapt, and overall, it prefers using fat for fuel instead of protein through ketosis.

Other Keto Flu Symptoms

Headaches aside, it’s common to experience some other keto flu symptoms in the induction phase, including:

  • Sugar cravings
  • Irritability
  • Nausea
  • Dizziness
  • Fatigue
  • Brain fog

How long it lasts

The duration of headaches and other keto flu symptoms really varies from person to person, but typically can range anywhere from a few days up to a month, and generally occurs within the first few weeks of starting the ketogenic diet.

So Why Does the Keto Headache Happen?

Simply put, keto headaches occur because of electrolyte imbalances, dehydration, and carb withdrawal. When adapting to the ketogenic lifestyle, your body will naturally begin excreting excess water, which can lead to weight loss, but also dehydration.

Being in the state of ketosis also has a strong diuretic effect, meaning your body is excreting both water and electrolytes—mainly magnesium, potassium, and sodium.

By flushing out the water in your body, you’re also flushing out these essential electrolytes needed for brain and body function With that being said, be sure to stay hydrated and to consume plenty of essential electrolytes while on keto.

How to Prevent the Keto Flu

At this point, you may be wondering how to best prevent keto headaches and ease the transition your body is taking by switching to a very-low-carb diet.

The key is flexibility. Optimize your body’s metabolic flexibility so it can more easily switch from one source of fuel to another.

1. Increase your fat intake

By indulging in more dietary fats, your body will more easily grow accustomed to using fats as its source of energy. Remember, fats are replacing carbs as the main source of fuel and calories, so you need to consume more fats than you were before.

You should be aiming for getting 65%-70% of your total calories from fats.

2. Have some salt with your water

Before scoffing at the idea of drinking salt water, hear me out. When on a low-carb diet, your insulin levels will naturally decrease, meaning your body will be unable to hold as much sodium as it may have been previously used to [4].

Remember that you’ll also be excreting excess water which could also contribute to a sodium deficiency. Boost your salt intake by adding a pinch of salt to your water or by consuming salty soups such as bouillon or bone broth.

3. Ease up on the protein

Too much protein on the keto diet can have a negative effect, especially during the induction phase.

Your body can convert excess protein into sugar through a process called gluconeogenesis. Try to keep your daily protein consumption at around 25-30% of your overall caloric intake.

4. Supplements

Don’t shy away from supplements! They’re a great way to help your body along in transitioning to fat instead of carbs for fuel. Just keep in mind that supplements are just that—supplements. They aren’t meant to replace your diet, but rather supplement it.

Using a keto electrolyte supplement can help ensure you’re getting the right amounts of magnesium, calcium, phosphorus, sodium, and potassium for optimal health.

5. Exercise

Related: Can You Exercise While On the Keto Diet?

Exercise is a great way to improve your body’s metabolic capacity. There is plenty of evidence showing that exercise effectively increases mitochondrial biogenesis, which in turn elevates your basal metabolic rate (BMR) [2]. In other words, exercise has fat-burning effects that extend beyond the time you spend in the gym.

6. Exogenous ketones

Supplementing with exogenous ketones is another effective method for boosting your ketone levels. This can be beneficial even if your body hasn’t fully converted to using fats as its primary energy source.

In the induction phase, you’re priming your body to prefer fats instead of carbs. By supplementing with exogenous ketones, you’re causing your blood glucose to decrease from increased insulin sensitivity.

These supplements also harbor plenty of essential electrolytes such as magnesium, calcium, and sodium, which your body greatly needs for optimal brain and body functioning.

Core BHB™ salts contain the perfect amount of magnesium, calcium, and sodium, along with 12 grams of BHB salts to boost your ketone levels and promote a smooth transition into ketosis.

Keep Your Head Up!

By embracing the keto diet, you’re already on the right track to a healthier lifestyle. Don’t be discouraged by the keto headache, instead, be proactive and prepared.

Now that you know what it is and how it occurs, you’re ready to take the right steps to prevent it or fight it.

The important thing is to keep your head up and stay positive. The keto diet is always a challenge in the beginning. Once you allow time for your body and mind to adjust, you’ll see its value and worth, and why you made this decision to begin with.


[1] Johnston AM, Horgan GW, Murison SD, Bremner DM, Lobley GE. Effects of a high-protein ketogenic diet on hunger, appetite, and weight loss in obese men feeding ad libitum. Am J Clin Nutr. 2008; 87(1):44-55. doi:10.1038/ejcn.2013.116. [PMC free article] [PubMed]

[2] Ruth C.R. Meex, Vera Schrauwen-Hinderling, Esther Moonen-Kornips, Gert Schart, Marco Mensinc, Esther Phielic, Tinek van de Weijer, Jean-Pierre Sels, and Patrick Schrauwen, and Mathis Hesselink. Restoration of Muscle Mitochondria Function and Metabolic Flexibility in Diabetes Type 2 through Exercise Training Is Paralleled by Increased Myocellular Fat Storage and Improved Insulin Sensitivity. Diabetes 2010 Mar; 59(3): 572-579.

[3] Tabata, I. Z. U. M. I., et al. “Effect of low blood glucose on plasma CRF, ACTH, and cortisol during prolonged physical exercise.” Journal of Applied Physiology 71.5 (1991): 1807-1812.

[4] Boden, Guenther, et al. “Effect of a low-carbohydrate diet on appetite, blood glucose levels, and insulin resistance in obese patients with type 2 diabetes.” Annals of internal medicine142.6 (2005): 403-411.