Keto flu-This, too, shall pass.

So you made the choice to commit to keto and suddenly you feel like dog crap. Your head hurts, you’ve got muscle cramps, and you swear you were just run over by an entire fleet of trucks. Congratulations, you’ve got the keto flu. Don’t worry, it’s not contagious, and it will pass very quickly.

What is Keto Flu?

Keto flu, or carb flu as it is sometimes called, is just your body arguing with you about making the switch to a low carb life. It’s not actually a virus like influenza, but some of the symptoms can feel similar. They can include but aren’t limited to:

  • Muscle soreness or cramping
  • Dizziness/nausea
  • Brain fog and confusion
  • Stomach pain
  • Fatigue
  • Headache
  • Intense sugar cravings
  • Irritability
  • Insomnia

Generally, keto flu surfaces within the first day or two of intense carb restriction and lasts about a week.  We are so used to running on carbs that giving them up can be difficult for a lot of people. Some people are lucky and don’t experience any of the withdrawal symptoms, but others get a full dose. If you are one of the latter, there’s good news. It’s actually pretty easy to lessen the blow.


What Causes Keto Flu?

Keto flu is your body’s way of dealing with the lack of carbs and processed foods. It is predominantly caused by an electrolyte deficiency, sodium being the biggest culprit. Symptoms of sodium deficiency can be:

  • Headache
  • Muscle spasms and cramps
  • Weakness or tiredness
  • Nausea/vomiting
  • In severe and prolonged instances, decreased consciousness and seizures

We know that insulin affects how we process sugar, but it also has an effect on our kidneys. When insulin is released, it signals the kidneys to hold onto sodium and water. On keto, insulin spikes are eliminated and levels even out.  While this is going on, the kidneys are no longer told to hold on to the excess sodium so it is released, taking a lot of water with it. With a lack of carbs available, the body also starts to use your stored glycogen for fuel. Because glycogen units are stored with water, as they get used, their water is set free as well.

These two processes are where the diuretic effect of keto come from, and also account for the rapid weight loss during the first week. Unfortunately, this is also the main cause of the keto flu.

In addition to sodium, other electrolytes can also be challenging to maintain on keto. The next most important being magnesium. Magnesium is so important to our daily function, yet most people don’t understand its full impact on the body. It is vital that you ensure you get enough every single day or it can have serious consequences on your health. Signs of magnesium deficiency can include:

  • Fatigue
  • Muscle spasms and cramps
  • Arrhythmia or irregular heartbeat
  • Dizziness
  • Nausea and vomiting, similar to vertigo
  • Numbness and tingling
  • Personality changes, such as confusion or irritability
  • Anxiety and panic attacks
  • Insomnia
  • High blood pressure

While following a ketogenic diet, you should be taking at least 300mg of magnesium per day. This advice was straight from my doctor as soon as I told him I was going keto. Of course, it is always best to get your nutrients from whole foods, but sometimes we just aren’t able to do that every day. If you are, great, you’re doing better than I am.

Rounding out the main electrolyte trio is potassium. Make sure you talk with your doctor before any supplementing of course, but be especially careful with potassium. There’s a reason it is part of the lethal injection cocktail, it’s serious stuff. While it is a very necessary component for healthy cell function, you can absolutely take too much.  Some signs of potassium deficiency include:

  • Weakness
  • Fatigue
  • Muscle cramps
  • Constipation

There is a salt substitute called Nu Salt that is mostly potassium chloride. Many of us, myself included, use Nu salt as a way to get our daily dose of potassium. I take a 1/4-1/2 teaspoon in a glass of water and chug it. How much I take depends on how short I am from my daily requirement. Again, I am not a doctor, this is not medical advice. Do some research, ask your doc and determine if supplementing potassium is right for you.

By now, you’ve probably noticed the similarities among the electrolyte deficiency symptoms and they all sound a lot like the actual illness, which is why we call it keto flu.

Another possible contributor to the keto flu may lie with a change in thyroid levels.  Several studies indicate that carbohydrate restriction can cause a drop in the thyroid hormone T3. Low T3 levels can contribute to fatigue, depression, and an inability to concentrate which have been observed when carbohydrates are severely restricted.

Some in the medical community view this as evidence that a ketogenic diet impairs thyroid function but that’s not the case. It simply means that your body is making the necessary adjustments according to its new fuel source. The body is a very efficient machine. The evidence suggests as the body adjusts to a low carb/high fat diet, thyroid hormone production is decreased because we just don’t need as much to operate efficiently.

In an effort to keep this post from going too far off topic, I will link a few articles  here (1,2) on keto and thyroid. I encourage you to read them especially if you are interested in learning more on the subject.

Best approach for dealing with keto flu.

Hydration, hydration, hydration. As if we weren’t tired of hearing that by now. But it really is the key to dealing with the symptoms and possibly avoiding them all together. 

As I said, keto is diuretic in nature. Water and electrolytes are rapidly flushed from your system in the first few days of keto. On average males need around 3.7 liters of water per day, and females need around 2.7 liters. In the beginning of keto, you should be aiming for slightly higher than these numbers until your body adjusts to its new way of eating. More information on water and its importance on health can be found here

Supplement electrolytes. You want to try to get your nutrients from whole foods whenever you can, but sometimes that can be difficult especially if you are just starting out. The switch to keto can be overwhelming as it is, without having to teaching yourself nutrition at the same time.

  1. Sodium- you should be getting about 5000 mg per day. This is why ketoers seem to salt everything. Most processed foods today are loaded with sodium. When you eliminate them from your diet, you are also eliminating most of your sodium. I drink sole water daily and I haven’t had any issues with being low on sodium. Let’s be clear though, I am not talking about shitty table salt. I am talking about unrefined mineral salt that hasn’t been stripped of all its health benefits. Pink Himalayan sea salt or celtic grey are great options. There are many ways to increase your salt intake. As I said, some people just salt all their food. You can also just shake some in your hand and toss it in your mouth. If you don’t use sole water, you can just sprinkle some in a glass of water and drink it. I add salt to many of the foods I cook. It’s up to you, just try to get in about a teaspoon a day.
  2. Magnesium- at least 300 mg per day. Actually, men should be getting around 400 mg per day and women 300 mg. I take about 500 mg because I am prone to migraines and upping my dose seemed to keep them under control. Again, how much I take generally depends on how much I get from my diet. Foods rich in magnesium are dark leafy greens, avocado, dark chocolate, pumpkin seeds, and almonds.
  3. Potassium- you want to shoot for around 3500 mg per day. You can take potassium pills but I’ve found that using Nu salt seems to be a better delivery system for me personally. This is definitely the component you want to get from whole foods if you’re able. I only supplement if at the end of the day, I see that I am way under the amount I need. This is why we say it’s so important to track your macros. Great sources of potassium include avocado, spinach, wild caught salmon, brussels sprouts, pumpkin seeds, and tomatoes.

Eat more fat!  Grill up a big juicy burger, throw on some bacon, cheese, chipotle mayo…go nuts! Too many people are stuck in the “diet means less food” mindset. Knock that shit off. Don’t be afraid of the bacon. Especially in the beginning, your body needs fuel to reprogram and power through such a drastic change. Good fats will keep you feeling full as well as prevent you from feeling like you’re depriving yourself because you are on “a diet”. I don’t know about you, but bacon makes my life happy.

One of the best sources of healthy fat is MCT oil. MCT oil is converted almost immediately to energy and is one of your body’s favorite fat molecules to run on. I use a tablespoon in my morning coffee and it keeps me going for hours. People add it to smoothies or shakes.  You can also cook with it up to 350 degrees, and it goes great in salad dressing mixes.

Do not starve yourself. That will absolutely make the symptoms of keto flu worse. The most important thing in the beginning is to keep your carbs under 20 grams per day. Don’t even stress about fat or protein, that will all come into focus. Track your macros, but don’t worry if you aren’t hitting all your numbers exactly. When you’re hungry, eat. Keeping keto friendly foods available will make the transition a lot easier. I always have certain foods on hand so I have no reason to ever deviate from my course. Cut up cheese cubes, pepperoni, macadamia nuts, almond butter, bacon, parmesan crisps, etc., have saved my ass on more than one occasion.

Get up and move around. Sometimes a good walk is what the body needs. While it’s not necessary to exercise to have success on keto, it’s definitely beneficial if you do. A sedentary lifestyle is so bad for the body in so many ways, not only physically but mentally. I’m not saying to get out there and run a marathon, but make an effort to get up and move around as often as you can. Exercise gets your heart working, your blood circulating, increases energy levels, and also helps you get better sleep at night.

Get sleep. Sleep can also really help ease or avoid the symptoms of keto flu. When you are tired, your body doesn’t have the juice to efficiently deal with the initial effects of ketosis, and the negative side effects can be amplified.

Once your body starts to settle in to a low carb life, the keto flu will subside. But just because you get past the first week, that doesn’t mean that you should slack on any of the above advice. It’s extremely important to continue to stay hydrated and to maintain you electrolytes or you could experience a resurfacing of the symptoms.

So in a nutshell:

  • Stay hydrated
  • Maintain electrolytes
  • Move your body
  • Get sleep

Thanks for reading. How did you deal with the keto flu? Or were you lucky enough not to feel the effects? I’d love to hear from you.




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