It’s a common misconception for those new to the ketogenic diet to expect an immediate physical and mental boost, but such is rarely the case.

For many (in reality, for most), switching to a strict low-carb diet like keto will leave your body experience a wide range of adverse symptoms. This is referred to as the “keto flu”, and happens typically within the first few weeks of a low-carb diet when your body begins flushing sodium and water out of the body.

This can leave you feeling tired, nauseous, and irritable, but fear not. Like most things in life, this too shall pass, and typically within a couple of weeks.

Another troubling side effect of a low-carb diet is dehydration and electrolyte imbalances. Luckily, since you’re reading this article, you’ll learn how to handle these bodily changes and deficiencies to keep you healthy.

What will be covered in this article: 

Dehydration and Fluid Loss

Sometimes referred to as the elixir of life, water makes up roughly 60% of our body weight, and is what every cell, organ, and tissue in our body depends upon to function properly.

Research has shown that many people simply do not drink enough water.

Every day, water is excreted through breath, sweat, urination, and bowel movements, and it carries essential nutrients to our body’s cells.

When we consume carbohydrates, our body converts them to glycogen, which is stored in our muscles and saved for energy. For each gram of glycogen that is stored, we gain roughly 2.7 grams of water. This water retention occurs because, in response to carb consumption, our kidneys hold on to sodium.

By drastically restricting carbohydrates, this leads to the body shedding water weight rapidly, which is why dehydration is the most common side effect of a ketogenic diet that you will likely experience in the first few weeks.

Dehydration can beget its own slew of unpleasant side effects, primarily constipation. This is one of the biggest challenges people on the keto diet face. Being constipated will leave you unable to maintain ketosis as it increases blood sugar and stress hormones.

While on a keto diet, constipation can also result from an electrolyte deficiency (especially potassium, sodium, calcium, and magnesium), and not consuming enough fibrous vegetables and fermented foods and drinks.

How To Remedy Dehydration

While on a ketogenic diet, your body will absolutely require a much higher intake of water, so drink up! This holds especially true in the first few weeks of the diet when your body is still adapting to the change.

While the amount of water consumption needed daily varies from person to person and depends on a variety of factors, including one’s health and environment, the general rule of thumb is to drink regularly and consume about 2-3 liters per day.

Electrolyte Imbalances

What are Electrolytes?

Electrolytes are essentially minerals (sodium, magnesium, and potassium) present in your body. They are necessary in the overall functioning of your muscles, heart, and brain, and work to regulate its processes, such as maintaining your body’s muscle action and blood chemistry.

How Electrolytes are Affected when Restricting Carbs

Electrolytes are found in your blood, tissue, urine, and other bodily fluids. On a low-carb diet, lots of electrolytes are flushed out of your system and need to be replenished. This imbalance of electrolytes can often result in fatigue, dizziness, headaches, and even muscle cramping—aka the keto flu.

Just like the issue of dehydration, electrolyte imbalance is an easy one to remedy now that you’re aware of its consequences.

The three primary electrolytes you need to replenish are potassium, sodium, and magnesium.

Potassium—This is the electrolyte most often lacking in the keto diet since it’s found in foods that don’t fit into the diet’s restrictions. There are some foods, however, that are both low in carbs and high in potassium, including salmon, avocado, and dark leafy greens. Beware, a severe deficiency in potassium could lead to risk of type 2 diabetes[1].

Sodium—Being in a state of metabolic ketosis leads to sodium being washed out of your body quicker. This occurs because when your insulin levels decrease during ketosis, the speed at which your kidneys extract sodium also decreases.

This can easily be fixed by adding more salt to your meals and consuming more broth. It’s important to know as much as possible about ketosis before you enter this stage to ensure the process is done so safely.

While high sodium intake typically comes along with a high calorie and high carb diet, which can result in increasing rates of hypertension and obesity[2], individuals on a low-carb diet actually need that extra sodium.

Magnesium—While a magnesium deficiency is the least common of the three electrolytes your body loses on a low-carb diet, if you’re experiencing symptoms like dizziness and cramps, you may need to support your diet with magnesium rich and keto-friendly foods like dark chocolate, avocado, mackerel, almonds, brazil nuts, and plenty more food items.

Electrolyte Drink

Apart from consuming electrolyte drinks for staying hydrated during sports, it’s also a very effective keto-flu remedy that will help boost the electrolytes your body is severely lacking on a low-carb keto diet.

There are plenty of electrolyte drinks out there on the market, or you can even try your hand at making your own using one of the many online recipes out there.

Now You Know

As Notorious B.I.G. eloquently puts it, if you don’t know now you know. While there are simply tons of resources, research, and studies available regarding the ketogenic diet, it can be difficult to consume it all.

If you have successfully made it through this article, you are now one step ahead of your unknowing keto brethren when it comes to safely navigating such a restricting diet by being equipped with the know-how in avoiding its nastier side effects, like the keto flu.

In summary, due to the natural loss of water and electrolytes, do your best to stay hydrated and get the potassium, sodium, and magnesium your body needs to continue functioning at its best.

More Readings:

5 Tips to Get You Into Ketosis Quickly

Can You Drink Alcohol on a Keto Diet?

Keto Constipation: What Causes it & How to Fix it

Dry Fasting Vs. Water Fasting: The Pros & Cons


[1] Chatterjee, R., Yeh, H. C., Edelman, D., & Brancati, F. (2011). Potassium and risk of type 2 diabetes. Expert review of endocrinology & metabolism, 6(5), 665-672.

[2] Song, H. J., Cho, Y. G., & Lee, H. J. (2013). Dietary sodium intake and prevalence of overweight in adults. Metabolism, 62(5), 703-708.

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Jessica Cotzin is a freelance writer, web developer, and avid traveler. Born and raised in South Florida, she graduated with a Bachelor’s Degree in Multi-Media Journalism from Florida Atlantic University and currently resides in Miami Beach. Her passions lie in reading great literature and traveling the world, bumping blindly into new adventures.


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