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What Are The Symptoms Of Keto Flu? – Adjusting To Keto

It’s very common for many who switch to a low-carb diet, such as Keto, to experience a period known as the “Keto flu” but what actually is it? What are the symptoms of Keto Flu? And why does it happen?

In this article we will look at what is actually happening during this process and how to deal with it if and when it does.

Symptoms Of The Keto Flu

Going through the Keto Flu can be quite unpleasant for many and can almost feel like the more common flu at times, but when you have gotten through it and your body has changed its energy source from glucose to ketones, you will experience restored energy, better moods with fewer cravings and appetite.

Some of the most common symptoms of Keto Flu are:

  • Headaches
  • Nausea
  • Brain Fog
  • Muscle Weakness
  • Fatigue
  • Diarrhea
  • Dizziness
  • Cramps
  • Insomnia
  • Heart palpitations

Luckily, these symptoms tend to last for around a week, but they may last longer for some depending on how their body adjusts into ketosis. It can take 1 to 3 days to enter into ketosis but it can take a few weeks for your body’s systems to become keto-adapted.

Why Does This Happen?

Our bodies have been used to its main source of energy coming from carbohydrates and when taking that away, it causes a big metabolic shift to its new energy source, ketones. This is a shock to the system and causes these unpleasant side effects.

Hormone levels will also be affected during this process too, particularly in the first few weeks and can affect weight loss (or gain) and energy levels.

In the first few days, you may experience rapid weight loss. This is due to your glycogen levels becoming depleted and your body retaining less water because of this. One molecule of glycogen attracts 3-4 molecules of water.

Make sure that to monitor and maintain adequate hydration during this period. Staying hydrated  can also help with reducing the effects of Keto flu.

Replace Electrolytes

When following the Keto diet a common deficiency that can occur in your body is due to lack of electrolytes being consumed. Electrolytes are very important for your nervous system, muscle function and maintaining balance, such as pH levels, within your body, so they are kind of a big deal…

The word “electrolytes” is a blanket term for the following minerals that are found in your blood, sweat and urine. These are:

  • Potassium
  • Chloride
  • Calcium
  • Magnesium
  • Bicarbonate
  • Phosphate
  • Sodium

As there are many restrictions in regard to the fruit and vegetables that are permitted on a Keto diet, it’s very important that you manage the amount of electrolytes you are consuming. This may include taking supplements.


Please see your doctor if you decide to take any supplements and follow correct dosage. Some electrolytes can be damaging to your health in high doses or if you have an underlying health condition.

How Many Electrolytes Do I Need To Consume?

The exact amount of electrolytes needed to consume has a lot to do with the amount of physical activity that you are undertaking and other lifestyle factors and you should try to aim for getting these naturally rather than by supplements, if you can. Keeping up your electrolytes may help reduce the severity of Keto Flu.


See below for recommended amounts:

Sodium (salt): When your insulin levels drop, due to the diet, so does your sodium. You will need to compensate for this and aim to consume 3000-5000mg of additional sodium. Don’t be afraid to add a bit of extra salt, however, try to avoid refined salts such as table salt.

Magnesium: Aim to consume around 500mg of magnesium. Good sources for magnesium are hemp and pumpkin seeds, kale, spinach, Brazil nuts, mackerel.

Potassium: As sodium levels drop, so does potassium. 4,500mg is recommended on Keto. Good sources for potassium are avocado, spinach, kale, salmon, cauliflower.

Calcium: Is found in many foods and its recommended to consume 1,000-2,000 mg per day. Try to get you calcium from such foods as broccoli, almonds, cheddar cheese, sardines, kale.


The above electrolytes are the most important to keep in check but there are many other micronutrients that need to be though about too, such as:

  • B Vitamins
  • Omega-3 Fatty acids
  • Vitamin A
  • Vitamin C
  • Viatmin K
  • Iron
  • Iodine
  • Phosphorus
  • Zinc

All of these micronutrients can be kept under control with foods that are acceptable on a Keto diet, but it’s a good to be aware of them and address them as you see fit.


Digestion Fun!

The first week or two of Keto can certainly be an unpleasant time with your bowel movements. The change to a low-carb, high-fat diet really shocks the system and can cause diarrhoea, constipation and gassiness.

It’s important to always stay hydrated and increase your electrolyte intake. Due to cutting out grains and certain fruits and vegetables, you may need to take a fiber supplement or make sure that you are eating enough Keto-friendly fiber rich foods, such as avocado, almonds, pecans, chia seeds, cauliflower, coconut and pumpkin seeds.

Avoid Strenuous Activities

Due to hydration and electrolytes being affected (as well as bowels) you should probably avoid strenuous activities until your body has properly adjusted.

If you are going to continue exercising through this period, you may experience discomfort from cramps, stomach pains or bowel movements.

Don’t Be Scared!

All that I have covered in this article can seem a daunting, as it seems like such a huge change, but you shouldn’t be too worried about it.

It’s all a matter of re-training yourself to eat differently and to really think about what you are putting in your mouth. It’s about checking your labels, researching some more and making better choices.

Once you push through the worst of it, the dreaded “Keto Flu,” you will have gone through the hardest part and it becomes so much easier.

You will have learnt what the best Keto foods to eat are and it will become second nature, just like riding a unicycle…


Please comment below with your own Keto experiences or questions.


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4 Replies to “What Are The Symptoms Of Keto Flu? – Adjusting To Keto”

  1. This is very interesting information about the “keto flu”. I’ve had a number of friends go on a keto diet for various reasons and most of them struggle with the keto flu at the beginning. I haven’t ever heard them mention electrolytes possibly being a way to minimize the effects of the keto flu. thanks for the information that can help a lot of people.

    1. Yes, it can definitely be a bit rough in the first couple of weeks for some. Can depend on a person’s lifestyle before switching to Keto too, as to the severity of it.

      Hopefully, your friends got through it OK and had some success from the diet. I’d be interested to hear how they have gone with it?


  2. Hello, Stevie and thanks for this info.

    First of all, I didn’t even know there was such a thing as a “Keto flu”.  I’ve had the flu and would really rather forget what going through that felt like :(. 

    I know that the Keto diet has helped many achieve their weight loss goals and other benefits but I don’t know if I could handle the “sick” part of it. 

    However, I am interested in some of the other information you included here like the info on electrolytes and the micro-nutrients.  We don’t use a lot of sodium in our diets (we do eat quite healthily and only use sea salt on our dinner and not even every day).

    The reason I’m interested in what you had to say about electrolytes is that I tend to get cramps in my legs, more at night than during the day and I’m kind of wondering if that has to do with a lack of electrolytes in my system? What would you recommend to overcome this?  I would rather go a different route than Gatorade if you know what I mean (way too much sugar).

    I have some friends who are on the Keto diet. I will be talking to them about what and if they experienced any flu-like side effects. 


    1. Hi Wayne, 

      It’s definitely a possibility that you may need some more electrolytes to balance your system, however, I can’t say for sure if this is the sole cause of your cramps as I am not a doctor and I wouldn’t want to make a diagnosis, there may be other things going on.

      It’s not going to hurt you to have a good look at what you’re currently eating and determine whether you are getting enough electrolytes and maybe correct it in your diet, if you find that you are not getting enough.

      You only need less than half a teaspoon of sodium to get enough salt that your body needs, but there is a lot of added salt in other foods, so it’s usually easy to go over that amount.

      If you are still having cramps, then it may be a different issue and probably best to see your doc.

      I’d be interested to see how you go with this. Drop me line with an update at a later stage, if you can?



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