Keto Flu; Its symptoms and how to beat it

If you’re anything like me, you took your time getting into the keto world. I had heard the theory of keto being tossed around by a handful of people who had unsuccessfully gone through several ‘pay to play’ programs. Then they had found Keto had lost a pile of weight because if it.  I watched from afar. I requested membership to several keto groups and in my uneducated state of mind, I guffawed at so many of the posts that came across my social media feed. These people had to be cracked doing this ‘Keto thing’ to their bodies. It couldn’t be good for you. Right?!?

The next step in my keto progress had me discussing keto and low carb with my doctor. I can still remember sitting in my Doctors office listening to her tell me about how the sugar industry lied to us over the years and much of what we had learned about nutrition was wrong and fat was really good for us. (Click here to read about what my Doctor told me)

Third step was diving head first into research and giving it a go myself. I discovered quickly that there was much to learn. I discovered to take baby steps and ease myself into the world of Keto. (Click here for the Keto 101 lesson) I realized that right from the get-go, I felt fabulous! Maybe there really was something to this keto/Low carb stuff.  I revelled in the new feeling of not feeling bloated.

Then IT hit! I was sitting in the living room with Hubby and Pa and I realized that I felt nauseated.  I didn’t think a lot of it at that point, I just put it down to something upsetting my tummy. Shortly after, when I got up from sitting, I realized the nausea was accompanied by the oddest feeling of being off kilter. I wouldn’t describe it as dizzy, or even light headed. It was more an airy feeling in my head and a sensation that something was not right. I didn’t want to say anything at this point.  Maybe I was over-reacting? Was I being silly? I quickly asked Mr. Google about keto side effects and stumbled upon a basic keto flu article and with it, the suggestion of drinking a cup of broth for temporary relief.

Easy, done! And fixed.

A couple of days later, Hubby and I were out driving and we were at a point where he was going back to work and I was to continue on with the vehicle by myself. It hit again, this time the off-kilter feeling was multiplied by a feeling of pressure in my head, a sensation of someone squishing my forehead and narrowing my field of vision. A weird headache that affected me so much, I held tight and stuck to Geoff’s side for balance. It was then that I realized that I couldn’t function like this and I certainly couldn’t drive. We stopped at a grocery store and bought a liter container of broth and I drank it as Hubby drove. By the time we reached his drop off point, I was feeling ok to drive but had a new resolve to figure this Keto flu thing out.

What is Keto Flu


Keto, or carb flu, is your body’s natural reaction to switching your diet from the typical American diet, to a carb restricted version. It is your body withdrawing from the carbs it has used for energy your whole life and instead, now switching from burning glucose to burning fat.  Your body is transitioning into a fat burning machine.

The keto flu. Yes, it’s a real thing, and it can happen when you drastically and suddenly remove carbs from your diet. While you feel terrible, you need to keep in mind that the keto flu is very temporary. Not only will these keto flu symptoms pass, but we can offer suggestions to get you through it quickly and without much fuss. Truth be told, we suggest you start these suggested actions before the keto flu even strikes. Nip that puppy in the bud before it even happens, but first, let’s take a quick look at why the keto flu happens when you go low carb.

Why does Keto Flu Happen?

Your body, up until this point has been sluggishly burning glucose or sugar (carbs) to survive. When you start a low carb or keto lifestyle, you restrict carbohydrates and your body must learn how to burn its backup energy source, fat. In order to do so, changes happen from the cellular to hormonal level.

Specifically, there are three changes that occur when you cut out carbs:

  1. Water and sodium flush:  When you restrict carbs your insulin levels drop, which signals your kidneys to release sodium from the body. This causes a loss of up to about 10 pounds of water weight as water shuttles sodium out of your body. (Yes, I’m sorry, that big initial weight loss is water weight and part of the keto transition.) This usually occurs in the first couple of days. Your glycogen and insulin levels drop in response to the lower amounts of sugar in your system. This causes dizziness, nausea, muscle cramping, headaches, and gastro issues, like diarrhea and constipation.
  2. Thyroid hormone levels decrease: Dietary carbohydrates and thyroid function are closely connected, so when you cut carbs, some Thyroid levels can also fall. This hormone helps to regulate your body’s temperature, metabolism, and heart rate. As your body adjusts to a ketogenic diet, lower hormone levels may leave you with brain fog and fatigue.
  3. Increased cortisol levels: A ketogenic diet tells your body that you’re in starvation mode and then it somewhat temporarily panics. In an effort to increase energy levels on a carb-restricted diet, your body triggers the release of stress hormones or cortisol. If you experience irritability and insomnia, that’s usually a sign that your cortisol levels have changed.

Keto Flu Symptoms

  • Sugar cravings

  • Dizziness

  • Brain fog/headache

  • Irritability/ Moodiness

  • Stomach pains

  • Nausea

  • Cramping

  • Lack of Concentration, Confusion

  • Muscle soreness / cramps

  • Difficulty falling asleep

  • Chills

  • Sore throat

  • Heart flutters / arrhythmia

Steps to manage Keto Flu.


When you switch to an extremely low carb ketogenic diet, you end up cutting out some of the richest natural sources of electrolytes, such as starchy fruit and vegetables. Replenishing your electrolytes is a great way to start feeling better fast. Take note of the key players – potassium, magnesium, and sodium. If you aren’t getting enough of them from your diet, which can be difficult to do on low-carb, incorporate them by-way of supplements.

  • Potassium: Never supplement potassium without consulting with your doctor there may be cardiac implications. Instead, eat fish, meat, leafy greens, winter squash. If you are battling cramps, constipation, or muscle weakness, go for potassium.
  • Magnesium: Magnesium Glycinate is the most bio-available formula. Citrate (mixed with Citric acid) is not recommended for long term as your bowels may become dependant on it to function. Eat spinach, chicken, beef, fish or supplement with 300-500 mg per day. Magnesium helps with keto flu symptoms like muscle cramps, dizziness, and fatigue.
  • Sodium: Particularly important as the keto diet is a natural diuretic and especially if you drink a lot of water. We recommend using Himalayan pink salt, supplement with 5,000-7,000 mg per day. Cramping is alleviated with proper sodium intake. On a Keto diet, sodium is your friend.

Low electrolytes play a big role in the onset of keto flu symptoms. Some people take an electrolyte supplement or drink at least once per day. Commercially bought Electrolyte sports drinks, typically contain processed sugar in some form, and are not recommended. Avoid these by making your own keto-friendly sports drink at home using 1 cup of water, 1 tsp Himalayan salt, and freshly squeezed lemon or lime juice.


Staying hydrated will help relieve headaches and boost your energy levels when you’re feeling sluggish. If you forget to drink enough water during the day, setting a ‘hydration’ alarm on your phone can help you remember, as well as keeping a full glass or bottle of water within reach at all times.

Drink Bone Broth 

Bone broth adds a serving of water to your diet and a dose of electrolytes – sodium and potassium – which will offset some of the discomfort you feel at a cellular level. Bone broth is also an easy way to sneak more water into your diet.

Eat More Fat

If your carb cravings are so intense, you’ve begun to dream of fresh baked bread, donuts, and pasta, skip the carb and eat the just the fats instead. Increasing your fat consumption can help speed up the adaptation phase. Have another tablespoon of coconut oil in your coffee or tea, snack on half of an avocado and some bacon, and especially MCT (Medium Chain Triglycerides) oil is different than most fats as it goes straight to the liver after digestion so it can be used immediately. Supplementing with MCT oil may even help you avoid keto flu altogether.

Gentle Exercise

Mild, and we mean MILD exercise, such as a yoga class, gentle walks or meditation, can help relieve muscle pain and tension and release endorphins to help boost your mood and motivation.

Get Lots of Sleep

 A good night’s sleep is a good thing when it comes to conquering keto flu. It keeps your cortisol levels in check, which will likely lessen your flu symptoms. Try for 7-9 hours a night, and use these tips to sleep soundly:

  1. Take an Epsom salt (found at any grocery store or pharmacy) bath to soothe and relax your muscles and improve electrolyte absorption.
  2. A keto friendly tea with a blend of herbs that promote restful sleep have a calming effect on your nervous system, and can help promote deeper sleep.
  3. The blue light from tablets, laptops, and smartphones can seriously interfere with your ability to fall asleep. Cutting off electronic use at least 2 hours before you go to bed, is an excellent way to improve your sleep quality.

Up your Carbs

If all else fails, up your carb intake. For some people, increasing fat simply won’t curb keto flu symptoms. If you’re tried everything else and even tested your limits by adding more fat and are still experiencing flu-like symptoms, you may want to up your carb intake just a bit. Sometimes we try to force the change just a little too quickly, adding a few carbs back in giving your body the chance to adjust to burning fat and ease the overall transition.


The biggest point I want to leave you with is, this is a very temporary passing phase. Hunker down, keep lots of broth (bouillon cube) on hand for immediate relief and nurse yourself along during this transition phase. With a little TLC and self awareness, you’ll quickly surpass keto flu level and leave it behind. You next exciting stage is fat adaption, where your body turns itself into the human equivalent of a locomotive train, one that has no problem staying on the tracks, efficiently burns its own fat for fuel and is on its way to being healthy, happy, fit and slim.

Keto on!

One Comment

  1. MaryLou Hall

    Bobbie, is it safe to say that…these symptoms will arise again during the initial 6 weeks if you don’t keep up on the magnesium,salt, potassium? The reason I’m asking is I got feeling a lot better from the flu symptoms, have had a set back….reread my keto flu section and realized that I have slipped up on my magnesium…I have been extremely busy and stayed strong with my electrolytes but not enough….sleeping a lot…high rate of beats per minute with my heart…..heavy head….oh my…

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