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Keto diets and electrolyte loss: how to deal with it?

Last updated: Oct 22, 2020 at 12:00PM | - Published on: Apr 5, 2019

Written by Sarah Neidler, PhD

Scientifically Reviewed by Raphael Sirtoli, MSc

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We’ve all heard the electrolytes are important to replace when you’ve just finished a gruesome sweat session, but not all of us know how our electrolyte needs change according to what we eat. With the keto diet, your body changes the way it handles electrolytes and water. This means that when your first switch from a standard carby diet to a ketogenic one, electrolyte loss and dehydration can happen.

But ensuring you’ve got enough onboard isn’t difficult. First, let’s start out with the basics.

What are electrolytes?

Electrolytes are minerals that carry an electric charge when dissolved in your bodily fluids, be it blood, urine or sweat. They are found in two locations within the body: inside your cells within the intracellular fluid (ICF) or outside your cells within the extracellular fluid (ECF).

Outside of the cell, the major electrolytes are:

  1. Sodium
  2. Chloride

Inside of the cell, the major electrolytes are:

  1. Potassium
  2. Phosphate

On top of these dominant electrolytes, we also have magnesium, calcium, and bicarbonate — all of which play important roles, as well.

While electrolytes may seem like a minor part of the bodily function, they’re actually pretty crucial moment to moment.

Electrolytes role in the body

Electrolytes play a major role in the body, and when we’re low on them or have imbalances, it can harm the body. Here’s why it’s important to maintain proper balance:

Infographic showing how electrolytes loss affect the body

Nervous system function

The nervous system functions on a system of electrical signals sent traveling between the brain and the rest of the body. These signals are electrical impulses generated when the electrical charge of a nerve cell membrane changes [1] due to the cellular inflow and outflow of electrolytes.

In order for an impulse to be transmitted, an exchange of sodium and potassium between the ECF and ICF must take place; sodium moves through the membrane to the inside, while potassium moves to the outside. This exchange between the inner and outer region of the cell causes the nerve impulse along the axon to fire. See muscle function (below) for a more detailed description on how an action potential is initiated.

Muscle function

In order for nerve impulses for muscle contraction to be transmitted, the proper balance of sodium and potassium is crucial. These minerals participate in creating the necessary action potential required for muscle contraction by moving in and out through the cell membrane. The pattern they follow is to gain a positive charge (depolarize), reach a maximum, lose that positive charge (repolarize), and finally settle back to the baseline charge [2].

Ultimately, it is the electrolyte calcium that floods the muscle cells, resulting in a cascade of interactions leading to muscular contraction. Magnesium and chloride also play roles in this. In fact, at rest, magnesium binds with motor proteins in cell and helps to maintain the relaxed state of muscles. Chloride also plays a role in maintenance of a muscle cell’s resting state.


Electrolytes are critically important during bouts of high intensity or prolonged physical activity. When we refer to electrolyte balance, however, we’re talking about the balance between water and electrolytes. Electrolytes, especially sodium, help to maintain normal fluid levels with the body.

The amount of fluid in a specific body compartment is regulated by the concentration of electrolytes present within it. When electrolyte concentration is high, fluid moves into that compartment, whereas if electrolyte concentration is low, fluid moves out [3].

As the body continually moves electrolytes in or out of cells, fluid levels fluctuate. Therefore, maintaining appropriate concentrations of electrolytes is critical to maintaining fluid balance within body compartments.

pH Balance

Several organs are involved in maintaining proper pH within the body:

  • Lungs
  • Heart
  • Pituitary
  • Adrenals
  • Kidneys
  • Blood vessels
  • Parathyroids

The body maintains a pH within a very narrow range of 7.35 – 7.45 via keeping the ratio of bicarbonate and carbonic acid around 20:1 [4]. If carbonic acid concentration increases (i.e. pH decreases), the body goes into acidosis, whereas if the bicarbonate concentration increases (pH increases), the body goes into alkalosis — both conditions can be associated with severe health consequences.

While the aforementioned systems all play a role in pH maintenance, the lungs and kidneys do the vast majority of work.

  • The kidneys function to retain or excrete sodium bicarbonate, as well as excrete overly acidic or alkaline urine. They also help to reabsorb sodium bicarbonate and secrete free hydrogen atoms (ions).
  • The lungs function to retain carbonic acid in the form of carbon dioxide, or rapidly excrete it by increases respiration rate.

When either of these buffer systems fail to maintain homeostasis, there is a resulting imbalance and pH changes.

So how are they regulated?

Electrolytes are regulated by a few different mechanisms:

The kidneys: The kidneys help maintain proper electrolyte concentrations by filtering electrolytes and water from the blood. They return some to the blood and excrete any excess into the urine for elimination.

The endocrine system: Antidiuretic hormone, ADH, is secreted by the endocrine system, which functions to maintain normal water balance within the body and keep sodium and potassium within normal limits.

The vascular system: The heart transports electrolytes in the blood to the rest of the body with every pump

The gastrointestinal system: The stomach secretes gastric juices, which are rich in chloride ions.

infographic showing How electrolyte are regulated in the body, from the cardiovascular system to the gastroinstestinal process

Together, the electrolytes work to keep your body functioning optimally and all systems working as they should. But individually, each electrolyte has its own unique function:

Sodium — As the main ion present in the extracellular fluid, sodium has a critical role in maintaining what’s called the osmotic pressure gradient. It exists between the inside of cells and their surrounding environment. Sodium comprises about 90% of extracellular positively charged minerals and therefore plays a very important role in electrical impulse transmission in nerve and muscle fibers. Sodium also plays a role in pH regulation, as well as some involvement in regulating cell membrane permeability [5].

Potassium — As the main intracellular mineral present in the body, potassium has a major role in regulating muscle contraction. It plays an important role in maintaining proper function of the heart muscle, ensuring it contracts and relaxes properly. Potassium also plays a minor role in maintaining proper pH [6].

Chloride — Chloride is another major extracellular mineral that, like sodium, also plays a role in maintaining proper extracellular fluid volume and osmotic pressure between the ICF and ECF [7].

Calcium — The majority of calcium in the body is contained in bones and teeth. It’s largely what makes bones hard and serves as a mineral reserve for the rest of the body. Calcium ions are necessary for muscle contraction, enzyme activity, blood coagulation, as well as stabilizing cell membranes and for the release of neurotransmitters [8].

Bicarbonate — Bicarb however is a negatively charged molecule and a by-product of your metabolism. It’s a major component of your blood and serves your buffer system (bicarb/carbonic acid) working to maintain your body’s acid-base (pH) balance [9].

Phosphate — Most of phosphate in the body is bound in bone and teeth as part of calcium-phosphate salts. Phosphate plays an important role as a component of phospholipids, which make up cell membranes, ATP, crucial molecules called nucleotides, and participate in crucial buffering activities like those mentioned above [10].

Why can keto lead to imbalances?

Many people experience the ‘keto flu’ when embarking on their keto journey. But the keto flu isn’t actually the flu at all — it’s a result of carb withdrawal and electrolyte imbalance. Electrolytes are found dissolved in fluids within the body, so when transitioning from a standard high-carb diet to a ketogenic one, you’re going to lose a lot of water coming from the glycogen stores you’ll be emptying.

Indeed, for every 1g of glycogen stored in the muscles and liver, 3-4g of water is stored with it. So as you deprive your body of carbohydrates, you will use up the glycogen stores and the water and electrolytes along with it, resulting in electrolyte loss. This is the factor explaining the drastic weight loss that can happen in the first few weeks on a ketogenic diet.

As we mentioned above, when we lose water on the keto diet, we also lose electrolytes. This is simply because they naturally dissolve in water. The main electrolytes we lose when starting on the keto diet are sodium, magnesium, potassium and calcium. It’s important to replace them according to your need.

By eliminating processed foods from the diet and restricting our total carbohydrate intake, we also may also be unwittingly lowering out salt (or sodium) intake. This is because a lot of low quality processed food like pizzas are high in sodium. Just to clarify, the sodium is not the problem per se here; it is the pizza.

How much water should I drink on a keto diet?

Drink to thirst. Granted, this may be harder for some than others. It’ll be likely harder if you hydrate a lot with flavored beverages or sugary drinks.

It’s good to follow both of your instincts to ‘salt to taste’ and ‘drink to thirst’ when trying to get the right balance of electrolytes on your keto diet. Ditching the sugars and flours that causes excessive fluid retention fluids will help normalize your electrolyte balance but just beware of the transition phase.

Don’t shy away from temporarily supplementing a few grams of salt a day and 100 mg of potassium when first adapting to the keto diet. LMNT is a great supplement to do that with, it contains 1,000 mg of sodium, 200 mg of potassium and 60 mg of magnesium.

Drink when you’re thirsty but don’t nurse a bottle all day long.

One of the great things about going keto is the results we feel, both physically and mentally. Improved energy, clearer thinking, greater focus, improved metabolic response, and so much more. But when we lack proper hydration because we’re not in the habit of applying smart and simple rules like ‘just drink water’, we potentially impair our body’s ability to function properly.

Studies have shown that improper hydration after exercising resulted in an increased number of headaches, as well as impaired concentration and mood [11]. Another study found that dehydration can cause cognitive impairments such as fatigue, impaired memory, and perception discrimination [12].

According to the United States National Library of Medicine, the average individual should be consuming anywhere from 2.7-3.7 liters of water per day [13]. These are a very vague estimate, so as with anything, use common sense and drink until thirst rather than stick to a rigid schedule (except if it’s a bare minimum).

Restoring electrolyte balance

Ensuring proper electrolyte levels is key to optimal body function, and in doing so, there’s less of a risk of experiencing the keto flu.

How much potassium do I need?

As potassium is critical to many functions within the body, general guidelines recommend a minimum of 1600 to 2000 mg of potassium daily [14], but amounts can range depending on the diet followed. On a ketogenic diet specifically, potassium can be obtained mainly through food sources. However, sodium loss is accompanied by potassium loss as well, so needs may increase. Around 2-3g (2,000-3,000 mg) per day is generally a good target to maintain adequate circulatory reserves [15].

How much sodium do I need?

During the first few weeks of keto, the body eliminates excess sodium and water, which forces it to adapt to a new balance of sodium intake versus excretion to maintain normal blood circulating volume. However, when the body becomes keto-adapted, dietary sodium is restricted (from the elimination of processed foods, carbohydrates etc.), so your brain and kidneys send signals to increase aldosterone and cortisol output. Essentially, the state of being in ketosis and restriction of salt intake can lead to increased stress on the adrenals [16].

As such, it’s incredibly important to maintain adequate salt intake to reduce excess stress on the body and keep it functioning optimally.

Dr. Stephen Phinney, a lead researcher in the ketogenic diet, recommends approximately 3–5g (3,000-5,000mg) of sodium per day (one tsp. of salt is roughly 2g of sodium) [17]. Dr. Phinney has used these values in his research and has found them to effectively maintain optimal circulatory sodium reserves. Even this is a conservative estimate, and some people find symptom relief even above 7g of salt a day, especially whilst keto adapting or going carnivore.

How much magnesium do I need?

Magnesium intake is just as important as sodium and potassium intake, as it’s also involved in many biochemical processes within the body. General guidelines for potassium intake are as follows [18]:

  • Males 14 to 18 years old: 410 mg
  • Females 14 to 18 years old: 360 mg
  • Males 19 to 30 years old: 400 mg
  • Females 19 to 30 years: 310 mg
  • Males 31 to 50 years old: 420 mg
  • Females 31 to 50 years old: 320 mg
  • Males aged 51 and up: 420 mg
  • Females aged 51 and up: 320 mg

Because magnesium is involved in blood sugar regulation, it’s important to ensure your levels are sufficient. Muscle cramps are often an indicator of low magnesium levels but not necessarily low dietary intake – how your body uses magnesium matters a great deal too. If you experience cramps, you might try adding magnesium-rich foods like avocados, supplementing it, or even going carnivore for a few weeks to see if it helps.

Where to get your electrolytes

Electrolytes are naturally present in foods, many of which are keto-compliant, so getting adequate amounts shouldn’t be a problem. Depending on how much physical activity you do, you may want to add in a bit extra to compensate for the excess loss.

Here are some of your best choices that are keto-friendly:


  • Avocado
  • Brussel sprouts
  • Mushrooms
  • Zucchini
  • Pumpkin seeds
  • Leafy greens (like kale)
  • Salmon (and other fish)
  • Coconut water (in small amounts due to its moderate sugar content)

Sodium: Sodium can be a bit tricky with keto since nearly all foods contain some. The best way to obtain adequate amounts is to season food (or knockback 1/2 tsp. at a time) of Himalayan pink salt.

  • Eggs
  • Lean meats
  • Sea vegetables (nori, kelp)
  • Cucumber
  • Celery
  • Salted nuts


  • Leafy greens
  • Avocado
  • Swiss chard
  • Pumpkin seeds
  • Cashew nuts
  • Seafood (salmon, mackerel, tuna)
  • Raw cacao


Whether it’s firing muscle contractions, maintaining the delicate pH balance, sustaining the activity of enzymes, or supporting acid-base buffer systems, electrolytes are crucial to fundamental bodily functions. The ketogenic diet, due to water loss and other mechanisms, leaves you more susceptible to experiencing electrolyte imbalance at first. So pay attention to your intake during that phase. There are many foods that are keto-compliant that will provide you with adequate amounts of electrolytes, but this doesn’t mean supplements couldn’t be of help.

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Written by Sarah Neidler, PhD

Sarah Neidler did her PhD in cancer research at the Beatson Institute for Cancer Research in Glasgow. She has a strong interest in nutrition and the ketogenic diet and believes that they are beneficial for the treatment and prevention of chronic conditions, such as heart disease and diabetes. She loves cooking, reading, sewing, Yoga, and CrossFit.

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