On Keto Flu and Electrolyte Imbalances

The “Keto Flu”

During the induction phase of a Ketogenic Diet, or even a Low-carb, Paleo Diet, some people may experience “flu” like symptoms (tiredness, lethargy, shortness of breath, even arrhythmia) that often makes one believe that what they are doing is not right for their bodies.

This “flu” is a manifestation of both mental and physical dependence on carbohydrates as the body is essentially going through a phase where it has to learn (or better said, re-learn) to use fats as fuel.

The most common sypmptoms of this ailment are:

  • Tiredness and Lethargy
  • Irritability
  • Lack of concentration
  • Muscle cramping
  • Heart palpitations
  • Slower or reduced bowel movements
  • Water retention / bloating (yes, too little sodium or electrolyte imbalances also cause water retention)

Tiredness and Lethargy

Most people who do a Ketogenic or Paleo Diet, initially end up cutting a lot of processed food. and when one cuts processed food, one also cuts a lot of sodium intake. Contrary to what we have been led to believe, sodium is not exactly bad for us, and we actually need to supplement with, as most animals do naturally.

To learn more about why current sodium guidelines are wrong, I suggest you read “The Salt Fix”, the new book by James DiNicolantonio, cardiovascular research scientist and doctor of pharmacy who overturns conventional thinking about salt and explores instead the little-understood importance of it, the health dangers of having too little, and how salt can actually help you improve sports performance, crush sugar cravings, and stave off common chronic illnesses.

When one cuts back on carbohydrates, one does not experience blood sugar spikes every time one eats and digests food, because well, one is hardly eating any sugar (all carbohydrates end up as sugars in the body). As a result, the body does not need to elevate circulating insulin levels to keep blood sugar at normal levels.

Under “normal” conditions, the kidneys tend to store and reuse a lot of sodium.

When your insulin levels are very low and stable, the kidneys through various hormonal mechanisms go into a diuretic type mode, excreting lots of sodium, potassium and water. The net effect is, IF ONE DOES NOT REPLACE SODIUM, to experience low blood pressure. [1] Symptoms of low blood pressure include, dizziness, weakness and fatigue.

Another aspect of this Keto-flu can include the nausea and diarrhea that many new keto dieters sometimes experience.

When one eats, all the nutrients in food are broken down into their constituent parts such as carbs (glucose), proteins (amino acids), fats (fatty acids) and fiber.

When one consumes fats, various pancreatic enzymes and bile salts from the liver and gallbladder all work to break down the fats/lipids down into cholesterol, triglycerides and other components. It takes time for the liver, gall-bladder and pancreas to up-regulate the production of bile/enzymes in order to accommodate a larger amount of fat that may be typical when switching to a Keto-like diet.

If one ingests a large amount of fat and the liver and pancreas don’t produce or have enough bile stores to break the fat down, one can get nauseated from this undigested fat.

Another thing that can happen with new keto-dieters is diarrhea. There is a diverse world of bacteria, yeast and other microorganisms that are part of the Human Digestive System. Sometimes, they are beneficial and assist in digesting food, and sometimes they are simply taking advantage of a free meal. Every organism in the gut is constantly vying for space and nutrients.

The average person has taken rounds of antibiotics or consumed a standard american diet with a lot of processed carbohydrates and alcohol, and so, probably has messed up the balance of the natural micro-flora, letting E.coli, H. Pylori and Candida A. start taking over where they shouldn’t.

This is called Gut Dysbiosis and is part of the reason a low carb, whole food approach to diet can be so beneficial for auto-immune disorders.

We now know 70% of our immune system is located in our gut ecosystem, and these gut bacteria have connections to our nervous system that can initiate cravings as if they were telling us to feed them with certain food.[2]

When one stops eating or reduces substantially carbohydrate intake, many sugar dependent microorganisms die from starvation. The corpses of these microorganisms can release chemicals and initiate inflammation inside the gut, leaving a person with a few days of diarrhea and nausea at the beginning of the low carb experience.

Keto flu can be treated by replenishing electrolytes: Sodium, Potassium and Magnesium.

The flu-like symptoms should dissipate in a few days or weeks, but it is still recommended to take care to get enough sodium, potassium and magnesium (a.k.a. electrolytes) in the diet, especially if one starts to experience fatigue, muscle twitching, headaches, muscle cramping, and in severe cases, arrhythmia.

Leg cramps may be the most common sign that electrolytes are out of balance.

Even if one goes out of the way to ingest table salt and foods containing potassium and magnesium, one may find the need to supplements. The minimum daily intake for the three electrolytes as suggested by Lyle McDonald is:

  • 5000 mg of sodium (not just salt)
  • 1000 mg of potassium, in the form of potassium chloride or potassium sulfate
  • 300 mg of magnesium, preferably in the form of magnesium citrate, aspartate or glycinate

Check our guide to Electrolyte Supplementation!

All these electrolytes should be preferably consumed in addition from what you get from your food; so then the TOTAL amount of electrolytes per day  would read:

  • 5000 – 7000 mg of sodium (not just salt)
  • 3,500 – 4700 mg of potassium
  • 350 – 500 mg of magnesium

Most people will not reach the suggested amounts with food alone and may have to supplement, so here are some good ways to reach your electrolyte requirements:

  • Sodium: Sea Salt, Colored Salt, Broth or Bouillon, Pickle Juice, LMNT Electrolytes.
  • Potassium: Raw Spinach, Avocado, Mushrooms, Salmon, Steak, Pork Loin, Lite Sodium Chloride.
  • Magnesium: Raw Spinach, Avocado, Magnesium Aspartate, Magnesium Lactate, Magnesium Threonate, Magnesium Citrate.

Make Ketogains very own recipe for Ketorade!

Or, you can buy LMNT, a tasty electrolyte drink mix that is formulated to help anyone with their electrolyte needs and is perfectly suited to folks following keto, low-carb, or paleo diets.

Slower or Reduced Bowel Movements

When starting a low carb / zero carb / ketogenic diet most people will experience less bowel movements and this may make them think something is wrong. In reality, people who reduce drastically processed carbohydrate ingestion report perfect digestion and bowel movement once the adaptation is over(this could be between 15 to 90 days).

The reduction in both fewer and smaller bowel movements, is due that meat and protein based foods are going to be absorbed at a near +90% rate by your digestive system, vs vegetable products due fiber and other indigestible compounds.

Also, being low in sodium may cause constipation: by reviewing sodium intake and making sure one ingests 5-7g sodium on a daily basis, most issues seem to be resolved.

As with many other things in Nutrition there is not a definitive stance on the importance of fiber, as some of the hypothesis (sometimes based om observational studies) have failed to been replicated in clinical trials.

More interesting articles on fiber consumption:

4 Good Reasons not to add fiber to your diet

Fiber: end the fantasy – myths / realities of an indigestible “nutrient”

Stopping or reducing dietary fiber intake reduces constipation and its associated symptoms


AIM: To investigate the effect of reducing dietary fiber on patients with idiopathic constipation.

METHODS: Sixty-three cases of idiopathic constipation presenting between May 2008 and May 2010 were enrolled into the study after colonoscopy excluded an organic cause of the constipation. Patients with previous colon surgery or a medical cause of their constipation were excluded. All patients were given an explanation on the role of fiber in the gastrointestinal tract. They were then asked to go on a no fiber diet for 2 wk. Thereafter, they were asked to reduce the amount of dietary fiber intake to a level that they found acceptable. Dietary fiber intake, symptoms of constipation, difficulty in evacuation of stools, anal bleeding, abdominal bloating or abdominal pain were recorded at 1 and 6 mo.

RESULTS: The median age of the patients (16 male, 47 female) was 47 years (range, 20-80 years). At 6 mo, 41 patients remained on a no fiber diet, 16 on a reduced fiber diet, and 6 resumed their high fiber diet for religious or personal reasons. Patients who stopped or reduced dietary fiber had significant improvement in their symptoms while those who continued on a high fiber diet had no change. Of those who stopped fiber completely, the bowel frequency increased from one motion in 3.75 d (± 1.59 d) to one motion in 1.0 d (± 0.0 d) (P < 0.001); those with reduced fiber intake had increased bowel frequency from a mean of one motion per 4.19 d (± 2.09 d) to one motion per 1.9 d (± 1.21 d) on a reduced fiber diet (P < 0.001); those who remained on a high fiber diet continued to have a mean of one motion per 6.83 d (± 1.03 d) before and after consultation. For no fiber, reduced fiber and high fiber groups, respectively, symptoms of bloating were present in 0%, 31.3% and 100% (P < 0.001) and straining to pass stools occurred in 0%, 43.8% and 100% (P < 0.001).

CONCLUSION: Idiopathic **constipation and its associated symptoms can be effectively reduced by stopping or even lowering the intake of dietary fiber.**

Water Retention / Bloating

Electrolytes play important roles in your body, including regulating water balance.

When electrolyte levels become too low or too high, they can cause shifts in fluid balance. This may lead to increased water weight (12).

You should tailor your electrolyte intake to your water intake. If you drink large amounts of water, you may need more electrolytes (13).

If you exercise daily or live in a humid or hot environment, you may need additional electrolytes to replace those lost with sweat (14).

In contrast, large amounts of electrolytes from supplements or salty foods, coupled with a low water intake, can have the opposite effect and increase water weight.

So, follow the recommendations as outlined before: start by balancing your electrolyte needs as we shared, and don’t go crazy on water intake. Water should be drank “to thirst” – no need to aim for +4 lts of water per day.



“During the first few days of Ketosis sodium and potassium are lost with the excretion of ketone bodies. If Ketosis continues, the obligate cation accompanying ketone bodies becomes ammonium ion.”
Comstock JP, Garber AJ. “Clinical Methods: The History, Physical, and Laboratory Examinations. 3rd edition”, Chapter 140 – Ketonuria.

“The diuretic (dehydrating) nature of ketosis causes an excretion of three of the body’s primary electrolytes: sodium, potassium, and magnesium (31,40). These three minerals are involved in many processes in the body, one of which is the regulation of muscle contraction, including the heart. Some studies show a net loss of calcium while others do not. (31).

And after about three weeks your muscles adapts to using mostly fat over glucose/ketones, allowing your glycogen stores to go up again. As described previously, muscles will derive up to 50% of their energy requirements from ketones during the first few days of ketosis. However, this drops rapidly and by the third week of ketosis, muscles derive less only 4-6% of their energy from ketone bodies. (22).”

“The Ketogenic Diet” by Lyle McDonald, page 46/47/79

“It takes a while to become fully ketone adapted. At first, the body is making the ketones, but the tissues haven’t completely converted to using them for energy yet. The body then wastes the unused ketones (which are highly caloric) in the breath and urine. As time rolls on and the body becomes ketone adapted, it wrings every smidgen of energy it can out of the ketones, so you don’t get as great a loss as you do early on.”

Micheal R. Eades, “Metabolism and Ketosis”.

[1]Effects of insulin on renal sodium excretion. Gupta AK, Clark RV, Kirchner KA. Source Department of Medicine, University of Mississippi Medical Center, Jackson 39216-4505.

[2] Gut microbiota: next frontier in understanding human health and development of biotherapeutics Satya Prakash, Laetitia Rodes, Michael Coussa-Charley, and Catherine Tomaro-Duchesneau