In Categories: Science & Research

Leveraging basic physiology to prevent ‘keto-flu,’ ‘Atkins-flu,’ and ‘adrenal fatigue.’

If we can believe what we read on the internet, ‘adrenal fatigue’ is a common problem associated with low carbohydrate, paleo, and ketogenic diets. Typical symptoms attributed to diet-induced adrenal failure are fatigue, insomnia, anxiety, and slow recovery after exercise. In past decades, these symptoms have been casually called the ‘Atkins- or keto-flu’. And the equally casual recommended treatment from internet nutrition gurus is to add back more carbs to your diet until these symptoms go away.

But here is an interesting puzzle…

If you google “adrenal fatigue ketogenic” at the time of this writing you get 371,000 hits. However, a PubMed search of the same three words yields zero hits.

Why? The simple answer is that ‘adrenal fatigue’ is not an objective medical diagnosis associated with a ketogenic diet, nor is it one that can be made based upon a physical exam or by lab testing. You can’t find its diagnosis and treatment described in medical textbooks or in peer-reviewed research papers.

The mere fact that adrenal fatigue does not appear in medical textbooks does not prove that it doesn’t exist. After all, ‘nutritional ketosis’ and ‘keto-adaptation’ have yet to be adequately described in those hallowed publications. But where’s the science linking carbohydrate restriction and/or nutritional ketosis to impaired adrenal function (i.e., inadequate cortisol or adrenaline production)?

Indeed, there is a somewhat complicated answer to this question that can link nutritional ketosis to fatigue, anxiety, and even insomnia. And yes, adding carbs to your diet could understandably reduce these symptoms. So, case closed, right? Absolutely not!

Cutting to the chase, most of the symptoms that the internet community attributes to adrenal fatigue and inadequate dietary carbs can be cured by a modest daily supplement of one essential nutrient – sodium (aka salt).

Caveat: To avoid confusion as we continue this discussion, we need to differentiate between ‘sodium depletion’—which triggers the renin/aldosterole pathway that reduces sodium excretion—and simple dehydration. Dehydration triggers thirst, which stimulates water consumption. But water consumption alone cannot reverse the symptoms of sodium depletion. Without enough sodium in the body, no amount of water intake can maintain normal volume in the circulation. Dehydration by itself tends to be self-correcting. Sodium depletion symptoms are less specific, and given our national guidelines’ phobia against salt, most people don’t respond appropriately.

Sodium – Essential But Still Controversial

Sodium has been recognized for thousands of years (and understood biochemically for over a century) as an essential mineral for human well-being and function, but the optimum level of intake for humans remains highly controversial. Sodium intake has been linked to increased blood pressure in about 25% of the general population, and given the strong association between hypertension and cardiovascular disease, the assumption has been that we all should consume less sodium to reduce our heart-attack risk. In other words, we are all told to limit our salt intakes because this is assumed to be benign for most of us and life-saving for the minority with what is called ‘salt-sensitive hypertension.’

While sodium restriction for everyone remains the official policy of most developed countries, there are many reasons to question this one-size-fits-all recommendation (Taubes, 1997). First of all, no one has bothered to do the obvious study in which people with normal blood pressure restrict their salt intakes for years at a time to see if this improves their overall health, or at least does them no harm. Absent that, the epidemiological data from large populations based upon reported salt intakes has generated a lot of conflicting data, with some studies showing increased risk associated with increasing salt intakes and some not. (Mozaffarian 2015, Graudal 2012, Mancia 2017) For reasons we will explain below, sodium restriction as a national policy is increasingly apparent as a house built on sand.

The Salt/Sodium Adrenal-Hormone Connection

Eat no salt for more than a few weeks and you die. Don’t eat quite enough salt long term and you will develop symptoms that are the same as those described for ‘adrenal fatigue’.

Sodium is an essential mineral found in your blood, specifically in your serum, and in the extra-cellular fluid that surrounds all of the body’s cells. Its level in the blood is jealously guarded by the actions of both your kidneys and adrenal glands. Eat too much salt and your kidneys accelerate its excretion. Eat too little and your adrenals make a hormone called aldosterone that causes your kidneys to conserve sodium, but in doing so they are physiologically obligated to simultaneously waste potassium. Wasting too much potassium is not good because your muscles, heart, and nerves need to contain the right amount of potassium to work properly.

The reduced amount of sodium available in the circulation that triggers the adrenal gland to increase production of aldosterone also increases adrenal production of the stress hormone cortisol and the fight-or-flight hormone adrenaline. Increased cortisol and adrenaline levels are stress hormones that are potent impediments of healthy sleep.

Bottom line: salt, potassium, adrenaline, and cortisol are intimately connected; and there is a clear relationship between inadequate dietary sodium and the purported signs of ‘adrenal fatigue.’

How Nutritional Ketosis Affects Your Sodium Needs

With adaptation to nutritional ketosis over a number of weeks, many basic functions of the body undergo profound changes:

  1. Fat (and ketones made from fat) replaces glucose as the primary fuel
  2. Sensitivity to multiple hormones, including insulin (Forsythe 2008, Boden 2005), leptin (Volek, 2009), and thyroid hormones, improves
  3. The kidneys switch from retaining sodium to rapidly excreting it (Spark 1975). This carries the cumbersome medical name ‘natriuresis of fasting,’ but its real name is normal sodium metabolism with nutritional ketosis.

For those of us who are prone to retain sodium (e.g., causing bloating, high blood pressure, congestive heart failure, edema/ankle swelling), this accelerated sodium excretion with nutritional ketosis is a blessing. But once any excess sodium and water have been cleared from the body in the first few weeks of a ketogenic diet, a new balance of sodium intake to sodium excretion then has to occur so that adequate blood circulation (aka , circulating volume) can be maintained. However if, in this keto-adapted state, dietary sodium is restricted, your brain and kidneys signal your adrenals to increase aldosterone and cortisol. What this means is that a combination of nutritional ketosis plus salt restriction leads to adrenal stress.

Nutritional ketosis + salt restriction = adrenal stress

Research Linking Ketogenic Diets to Adrenal Stress

In our book The Art and Science of Low Carbohydrate Living, we describe a classic but seriously flawed human research study we have labeled ‘The Yale Turkey Study’ that was published in the New England Journal of Medicine (DeHaven 1980). This group of prominent medical scientists gave overweight subjects 400 kcal per day either as boiled turkey or as a 400 kcal combination of boiled turkey plus grape juice for a month or more. Sodium intake was tightly limited. The subjects receiving the ‘turkey only’ diet had 5-fold greater ketones, much lower blood pressure on standing, and prominent symptoms of fatigue. Most importantly, after weeks of stimulation to try and maintain normal blood pressure, their adrenaline levels were markedly reduced (i.e., depleted); whereas those patients fed turkey plus grape juice maintained normal adrenaline production.

Cortisol levels were not reported in this study, but they were likely elevated for the first few weeks in the subjects given the ‘turkey only’ ketogenic diet. And had this sodium-restricted turkey diet been continued for more than a month or two, cortisol production would have fallen as the adrenal glands finally failed to keep up. But is this a problem of nutritional ketosis, or is it due to severe salt restriction in the face of increased sodium excretion by the kidneys?

In a recent study comparing a ketogenic diet with 4% of energy as carbs to a diet with 35% of energy as carbs, after 1 month the low carb subjects had increased production rates for cortisol (Stimson, 2007). Nowhere in this paper do they mention dietary sodium/salt intakes, but since it was performed in a metabolic ward overseen by well-trained dietitians, it is almost certain that daily sodium intake was restricted to less than 3 grams per day. The increased production of cortisol, a sign of stress, was unlikely due to nutritional ketosis per se, but instead caused by the combination of salt restriction during the ketogenic diet.

And what about all the rest of the research showing that a ketogenic diet is harmful to the adrenal glands? Well, despite the hundreds of published studies of humans on ketogenic diets lasting as long as 2 years, there is little else that could be considered credible scientific evidence for adrenal damage or fatigue.

Research Showing Normal Blood Cortisol During Ketogenic Diets

Again, there is not much to report here — just one paper by one of us showing that serum cortisol levels remained normal in 12 men given a well-formulated ketogenic diet for 6 weeks (Volek, 2002). Why so little published data showing normal adrenal function when a low carb diet is properly formulated? Perhaps because:

  1. If you looked and didn’t see an obvious medical problem occurring, why study it again and again?
  2. Medical journals don’t get excited about publishing normal data

Is it Safe to Recommend Adding Salt to a Ketogenic Diet?

The risk of salt in the diet has been vigorously debated for over a century (Taubes 1998), and that debate continues to this day. However there are two important points to be made in the context of this discussion. First, since nutritional ketosis accelerates sodium excretion by the kidneys, whatever risk might be associated with too much sodium at any one level of salt intake would be less during ketosis than when eating a high carb intake. Stated another way, a high carbohydrate intake suppresses the body’s natural ability to excrete sodium and thus reduces a person’s ‘salt tolerance.’ The details of this carbohydrate effect are not fully understood, but insulin is known to be involved in renal sodium metabolism (DeFronzo 1981).

The second important point is found in a recently published study that threatens to derail the whole anti-salt crusade. An international group of scientists collected urine samples from over 100,000 adults in 17 countries and then observed their health status for 4 years (O’Donnell 2014). What they reported was that people consuming less than 4 grams of sodium per day had a sharply increasing risk of death, almost doubling when they got down to 2 grams/day of sodium. In contrast, with higher sodium intakes, the risk of death rose very slowly beginning with intakes above 6 grams/day.  For example, as shown in the diagram below, mortality risk was increased by only 15% at 8 grams/day.

Estimated sodium excretion and risk of death from any causeSodium intake and mortality

Optimum Sodium Intake During Nutritional Ketosis

Over the last few decades, our recommended sodium intake for most people during a well-formulated ketogenic diet, based upon the amount needed to avoid the symptoms of ‘Atkins flu’ or ‘adrenal fatigue’, has been 5 grams per day (3 grams in your food, 2 grams from broth/bouillon). This longstanding clinical observation of ours is now validated by this recent Canadian research.

That said, there are still variations between individuals that necessarily modify this advice.

  1. People with high blood pressure or fluid retention that persists after keto-adaptation, and particularly if they are taking a diuretic medication, should not increase their sodium intake above 3 grams per day until these symptoms are resolved and the diuretic medication stopped.
  2. People routinely taking NSAID medications like ibuprofen (Motrin, Advil) or (Aleve, Naprosyn) are more ‘sodium sensitive’ because these drugs block salt excretion by the kidneys and raise blood pressure (Zawada 1980).
  3. Heavy physical exercise in the heat will cause increased sodium loss in sweat, which can increase one’s daily sodium requirement above the 5 gram level.

And finally, as always, it is important to distinguish between grams of sodium and grams of salt.

Salt and sodium are not the same.

1 teaspoon of salt = 5 grams of salt = 2.3 grams of sodium
(the rest is chloride)

There continue to be very strong biases in the medical mainstream against both dietary salt intake and ketogenic diets. Most doctors and dietitians have been trained to fear both. From a marketing perspective, if we were smart, we’d get on the bandwagon and preach adding carbs to suppress ketones and prevent fatigue. That would be a political winner!

But our own research and high quality studies published by others continues to lead us to embrace the scientifically correct but politically contrarian view. Nutritional ketosis is good for you. In particular, given the emerging view of ketones as both a fuel and beneficial epigenetic signal, there is unique therapeutic value to nutritional ketosis that we are loath to ignore. And all that is needed to capture these benefits is to supply the modicum of daily salt intake required to maintain an optimum balance of sodium and potassium in the body.

Ask yourself this question: if nutritional ketosis has been shown to markedly increase my defense against oxidative stress, and it also makes mice and worms live 13-26% longer, why would I give up these advantages just so I could eat sugar and refined carbs?

We won’t go so far as to say that the ‘adrenal fatigue’ myth was invented to scare you away from nutritional ketosis. More likely, its proponents just don’t understand the electrolyte and mineral metabolism changes that occur during nutritional ketosis.

So praise the science, and please pass me the salt.

Have more questions about nutritional ketosis? Check out our FAQ by Dr. Steve Phinney and the Virta team.


  1. During my 4 years of ketogenic diet (about 5 grams of net carbs per day) i got 5 kidney stone all related to my salt intake who was about 4 grams of sodium per day.
    My water intake was about 2.5 to 3 quarts per day so i think i was well hydrated.
    I really seem to have trouble with salt/sodium.
    Never had a kidney stone before the ketogenic diet and didn’t have any problems since restart a more low carbs approach of about 100 grams of net carbs per day.


    1. Salt intake doesn’t really have anything to do with kidney stones. Most are caused by calcium oxalate deposits (often exacerbated by metabolic disorders) or from a buildup of uric acid, usually caused by too much protein in the diet. A truly ketogenic diet would encourage neither issue.


      1. Manuel Cachafeiro MD. October 6, 2018 at 11:25 pm

        The ketogenic diet center of the Johns Hopkins Hospital recommends adding potassium citrate as a supplement to the ketogenic diet to reduce the risk of kidney stones in an important way.


    2. 100 net carbs is not Ketogenic, you need to lower your carbs much more and is probably why you havent gotten more kidney stones since going lower. 20g net carbs is the general rule, some like myself go more carnivore/zero carb. idea is as little carbs as possible and still feel good!


      1. You didn’t read the original commenter’s post properly – he WAS ultra-low carb when keto. Sebastian said when he was on the ketogenic diet he ate 5 g of carbs per day. Subsequent to struggling with kidney stones, he shifted to a looser “low carb” approach (as opposed to keto) and his total net carbs were 100g per day.


    3. The book “Anyway You Can” by Dr. Annette Bosworth explains why kidney stone attacks happen on beginning ketogenic diet. Stones form before the diet begins because they are impossible to form in while in ketosis. The ketogenic diet starts dissolving them. They will dissolve in place without falling out of kidneys if ketogenic diet is maintained. If carb addiction causes diet swings in and out of ketosis then the alternate dissolving and building of the stones can break them loose from kidney which is then what people call “having kidney stones.” You always had the kidney stones, but they were cemented to the kidney until keto started dissolving them. Standard Process PhosFood will dissolve kidney stones quickly, this would be prudent to use before starting keto if you know you are at risk.


    4. That was way too much water considering you only need about 8 cups a day from all sources (nkt drink 8 cups a day as mistakenly advised). I doubt it was kidney stones from salt. More likely all the extra minerals in the water you were drinking!


  2. I have been experiencing fatigue(especially in the morning and during the day), chest pressure, shortness of breath, being unable to fall asleep at night.. Along with bad digestion, bloating,constipation( Also have been diagnosed with h.pylori recently)


    1. Virta Health
      Virta Health May 4, 2018 at 9:13 pm

      Sorry you have been experiencing issues! You can try out keto FAQ to help troubleshoot:


  3. Hi Virta Team,

    I am successfully doing a Keto diet and unlike my fellow Keto’ers, I am not experiencing a diuretic effect or needing more salt.

    I am TOFI and so not doing Keto for weightloss and hence not experiencing water weightloss.

    I’m trying to understand why my kidneys are not excreting increased levels of sodium and why I’m doing well just eating my normal salt levels.

    Sure, I may be a genetic freak : )

    But I thought you might have some insight for me. Thanks!


  4. How is keto modified when someone has an aldosterone producing adenoma (Conn’s syndrome) ? I can see keto helping in keeping sodium down but added sodium would get into the aldosterone receptors that caused all the problems P.A. produces with the heart, kidneys etc.?


    1. Virta Health

      Thanks for your question! Dr. Phinney said he is not aware of any specific published research on the use of a well-formulated ketogenic diet in managing patients with Conn’s syndrome.


  5. I have addisons can I keto???


    1. Virta Health

      People with Addison’s disease typically need daily replacement of adrenal corticosteroids, including both the stress ones and those that help manage minerals. When switching to a ketogenic diet, these medications may need to be adjusted, and this requires the expert guidance of a physician (preferably an endocrinologist) with experience managing nutritional ketosis.


  6. I read the book The K Factor which suggest we need a potassium:sodium ratio of 4:1 or greater! I notice you’re recommending about a 1:2 ratio. Do you know that book and what would you say about it?
    I noticed a dramatic difference in my relationship with water when I went low-carb and grain-free. I seemed to need dramatically less water, peed less, and actually had an aversion to drinking more than a little each day (but I felt good, aside from cramps at night). I believe my body was trying to conserve electrolytes that I wasn’t taking enough of. Now I drink lots of water with magnesium, trace minerals, potassium and sodium and I love it. No more muscle cramps. But I want to get the ratios right.


    1. Virta Health

      We are glad to hear that you have worked to improve your electrolyte intake. We recommend 3000-5000mg of sodium and 2000-3000mg of potassium on average when consuming a well-formulated ketogenic diet.


      1. Can you please explain how you ended up with these numbers? The USRDA for potassium is 4,700mg per day, so I’d like to know why you recommend less, but mainly I am curious about the ratio per TanyaKH’s question. Does keto cause us to excrete sodium at a much higher rate than potassium? How would we know when we have the correct ratio in terms of what “stays” inside the body?


        1. Virta Health

          Hi Jeremy, Here are some recommendations from Dr. Phinney and the Virta team. and I hope that helps!


      2. How many teaspoons does 3000-5000 mg of sodium equal? I got the Keto flu after drinking Ketones for a month and could never drink them again because each time I would get fatigue , constipated and could not sleep at all . I was salting my food like crazy and drinking lots of water and talking Potassium and Magnesium tablets. I have suffered from Lyme’s disease in the past and it brought a relapse on. Adrenals were definitely affected.


        1. Virta Health

          Replenishing your sodium is important while following a ketogenic diet. Here are Virta’s recommendations:


  7. Berkeley Elison August 27, 2018 at 4:23 am

    Any recommendations for a person with a TBI 40 days ago and on parenteral inpatient nutrition? Are there any neuro clinicians that make a LCHF type tube feeding?


    1. Virta Health

      This is as specialized medical question that would require detailed and ongoing involvement by expert professionals. This expertise is most likely found in a university neurology clinic that treats people with seizures using a ketogenic diet. The Charlie Foundation ( may be helpful in finding such a clinic near you.


  8. While I don’t see it correlated to ketogenic diets but more from the SAD and acute stress we do test lab testing for adrenal fatigue and physicians can diagnose it from physical exam. We do it all the time in functional medicine.


  9. I’ve had low adrenal/thyroid symptoms for 30 years, and I crash when I reduce carbs. My labs confirm the low hormones. I feel better when I travel and your article helped me realize it’s the (high salt) restaurant food. I normally only eat 1 tsp/day of salt, and I thought that was a lot. So called adrenal experts never say you need 3 teaspoons a day to heal adrenals, they just say “eat more salt,” but if you’re raised in an anti-salt world then 1 tsp seems like a lot.

    Question: Should I resolve my adrenal fatigue by eating your recommended amount of salt for a few months before I start ketogenic diet?


    1. Virta Health

      Hi Rich, Great observation on how your body responds to salt! We aren’t able to provide specific medical advice via this forum. We’d encourage you to work with your provider to come up with a plan that works for you.


  10. I have been on a strict Keto diet for a month and still having the “Keto flu”. I normally have high potassium levels and have to take Kayexalate from time to time to lower it. I’ve always eaten lots of salt, but now more than ever on Keto. Will my potassium level ever level out on Keto? When it’s high I get an ongoing headache. Thanks.


    1. Virta Health

      Unfortunately, we are unable to provide specific medical advice via this forum.


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