8 Common Keto Flu Symptoms And Side Effects Explained

What Are The Symptoms of Keto Flu?

  1. Sugar Cravings
  2. Dizziness
  3. Poor Concentration and Focus
  4. Irritability
  5. Nausea
  6. Stomach Cramps
  7. Muscle Soreness
  8. Insomnia

You are probably already familiar with the high-fat, low-carb diet called the Ketogenic diet.

And, the Keto diet places the body in a state called ketosis, and during which, your body experiences side effect symptoms referred as the “Keto flu.”

… Ouch

Are you ready to read about the flu like Ketogenic symptoms and cure them all?


Below are some essential facts about these symptoms and their underlying causes.

Keto Flu Symptoms – What Are They And How Long Does Keto Flu Last?

8 Common Keto Flu Symptoms And Side Effects Explained
Keto Causing Headache, Nausea & Other Flu Like Symptoms

Many experience the following flu like symptoms within 24 hrs of restricting carbs.

1. Sugar Cravings

The earliest, most common side effect of the Ketogenic diet is strong cravings for sugar and starch.

It is partially a physical craving, but is also a result of a reaction in the brain’s reward center when it is deprived of endorphin-producing foods such as chocolate or other high-carbohydrate “comfort” snacks.

This symptom is typically one of the first to cease after a few days of following the Ketogenic diet, after which Sugar Cravings usually plummet.

2. Dizziness

Dizziness is a very common symptom of ketosis, and although it may be a bit scary, this side effect is almost always harmless.

It has to do with the body’s electrolyte balances, which are temporarily disturbed by the low-carb diet.

Although it is harmless overall, those who experience this symptom should not drive or participate in any activity to avoid any potential injuries resulting from losing one’s balance or falling.

3. Poor Concentration and Focus

Poor concentration and focus, more commonly referred to as “brain fog,” is simply a lack of focus that occurs when the brain is no longer being fed raw sugar and simple carbohydrates on a regular basis.

This symptom usually only lasts until the body is firmly into ketosis.

After going into the ketosis state, it will break down the stored fat stores to supply the brain with energy.

4. Irritability

It usually ceases within three to four days when you’re on the Keto diet.

5. Nausea

Nausea is also a common side effect of the Ketogenic diet when the body is feeling the deprivation of carbohydrates and sugars.

Once again, after the body has reached the state of ketosis, this symptom abruptly stops.

6. Stomach Cramps

Stomach cramps remind you how you’re going through a diet change during the first week of carb restriction.

7. Muscle Soreness

Although it feels similar to the muscle soreness experienced after a vigorous workout, it usually comes and goes in a random pattern and it lasts a week or longer.

8. Insomnia

Insomnia is a very common side effect of a low-carb diet, and most individuals who follow this diet usually experience this symptom for up to a week or two.

Keto Flu – Why Does It Occur?

Why Keto Flu Occurs Image
Understanding Why Keto Flu Occurs

When the body switches over to burning stored fat for energy, it must go through Keto-adaption referred as beta-oxidation.

In addition, Metabolic flexibility describes how well a person will adapt to switching from carbs to fats that is associated with the Ketogenic diet.

Basically, your level of resistance to the low carb consumption typically determines the length and severity of these symptoms.

If you have little or no metabolic flexibility then the diet change leads to the common Keto flu symptoms.

Kidneys Preserving Sodium and Water

  1. Insulin transports sugar and simple carbohydrates into cells where they can be used as fuel.
  2. It sends signals to the kidneys to preserve water and sodium.
  3. When insulin levels drop quickly and you lose water weight in less than a week when following a low-carb diet.

This is also true of glycogen, which is sugar in its stored form.

Water levels and glycogen are directly connected, and when carb intake is restricted for a few days, glycogen stores in the muscle are reduced.

Glycogen is responsible for water retention, so when its levels fall, so do our water levels, and to the average person, the diet appears to be working.

Bottom Line: The combination of low insulin levels and glycogen loss causes the elimination of enough sodium and water to lead to gastrointestinal issues, headaches, muscle cramps, nausea, and dizziness, which are some of the most common Keto flu symptoms.

As you might suspect, replenishing minerals and fluids is a good way to alleviate all or most of these symptoms, at least to some degree.

Although consuming eight, 8-ounce glasses of water per day is believed to be adequate water intake for healthy adults, those following a Ketogenic diet may wish to up their water intake substantially, particularly during the first seven to ten days of the diet.

Decreased T3 Thyroid Hormone Levels

Numerous research also indicates that thyroid function is linked to carbohydrates to an even greater degree than caloric intake.

One study found that carbs are an essential regulatory factor in T3 production.

T3 is three to five times more biologically active than T4, the latter of which is the thyroid hormone the human body produces in the greatest quantities.

When T4 levels are abnormally high, they reverse the effectiveness of T3 levels, which can lead to lower physical stamina.

Nevertheless, it is important to understand that this does not mean any permanent change is taking place in the thyroid gland, and it merely leads to the initial symptoms associated with carbohydrate restriction.

Increased Cortisol Levels

When stored fat is being burned regularly, the body no longer craves sugar and starch, which leads to releasing a deluge of stress hormones, including cortisol.

Not surprisingly, several negative side effects are associated with this release of cortisol, such as irritability, confusion, lack of energy and in some cases, muscle pain.

However, during ketosis, you do not have big insulin swings and these symptoms only last for a short duration.

Simply put, your body has adapted to a new metabolic function and the symptoms outlined above fade away and do not return.

How to Cure Keto Flu Symptoms

Keto Diet
Remedy and Cure for Keto Flu = Replenish Your Electrolytes

Let’s face it:

The best way to remedy your Keto flu symptoms is to look at where they might be coming from.

Here are some helpful tips for managing these symptoms:

  • Take a Magnesium Supplement – Take at night before you go to bed.
  • Replenish Your Electrolytes – Focus on replacing the main ones, including sodium, magnesium, and potassium.
  • Make Sure You Have Enough Fat – Choose healthier fats like coconut oil, olive oil, and avocados.

Bottom Line?

Whether you’re on the Keto, Paleo, or any other low carb diet, you’re going to experience some physiological changes in your body.

Some symptoms occur as a direct result that you’re entering into the state of ketosis.

Be sure to …

  • Replenish your electrolytes
  • Stay hydrated

… and pretty soon, you should be able to cure these Keto related flu like symptoms.

Excessive amounts of sugar cause inflammatory responses in the body that can lead to a host of illnesses and disorders, particularly later in life.

For this reason, fighting through a few initial symptoms associated with Keto flu is usually well worth the results.

Fortunately, because the symptoms of the Keto flu last only five to seven days in most cases, they have no long-term harmful effects.

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