If you are just getting started on the ketogenic diet and you are feeling dizzy when you stand up, generally tired or fatigued, irritable and on edge, nauseous, your stomach hurts, headache or you just can’t shake the sugar cravings you may be experiencing the dreaded Keto Flu.

The Low Carb Flu, Why Me?

Almost everyone feels it on some level when first getting started and some worse than others, but a virus like the traditional flu does not cause it. The “low carb flu” happens when you abruptly reduce or remove the high carb intake from your diet and move away from burning glucose (sugar) for energy to burning available fat to fuel your body.

Think about it for a moment. You’ve spent a lifetime eating lots of carbs and as you go through this short transition period of relying on glucose to relying on fat, but these symptoms will subside as your body adapts to this new way of eating.

Make sure to keep reading for our suggestions to combat the keto flu and make a smooth transition into ketosis.

Common Keto Flu Symptoms

keto flu symptomsMost people begin to feel symptoms of the keto flu within the first few days of restricting carbohydrates, and they usually subside within a week or so.

Of course, everyone is different, and it can be shorter or longer depending on many factors but here is a list of common symptoms in no particular order that you may encounter when first getting started on your path to ketosis and ultimately to your end goal of becoming fat adapted.

  • Confusion
  • Constipation
  • Cramping
  • Diarrhea
  • Dizziness or Light
  • Headed
  • Fatigue
  • Headaches
  • Heart Palpitations or Increased Heart
  • Rate
  • Insomnia
  • Irritability
  • Mental Fogginess
  • Muscle cramping
  • Muscle soreness
  • Nausea
  • Poor focus
  • Lack of
  • Concentration
  • Stomach pains
  • Sugar cravings

So, before you get discouraged after hearing about all these potential symptoms of the keto flu, let’s talk about how long you might feel some of these not so comfortable effects of adapting to keto.

How Long Does The Keto Flu Last?

The good news is it is brief and usually only lasts a few days to a few weeks at most. Trust me; it’s worth it once you get into ketosis and start to see the amazing effects the keto diet has on your mind, body, and life overall.

Depending on your lifestyle and how you’ve been eating before deciding to go keto, and your genetic makeup will impact how you experience the withdrawal symptoms from a high carb diet.

Someone who typically eats lots of fast food, processed foods and foods high in sugar are more than likely going to have increased keto flu symptoms when transitioning away from carbs than someone who is used to eating lower amounts of sugar and less high carb foods.

When we take into account the role genetics play and how some people are naturally much more metabolically flexible which means the capacity for the body to adapt fuel oxidation to fuel availability so that some people can make metabolic shifts more smoothly.

It’s clear that we all experience the symptoms and effects transitioning into ketosis differently, but whats happening on the inside of our bodies that contribute to the keto flu and our adverse reaction to reducing carbs.

What Else Causes the Keto Flu?

Several things contribute to the ketogenic flu including the loss of electrolytes and water along with the withdrawal from sugar. Several studies and articles across the web discuss keto’s effect on the decrease in T3 thyroid hormone levels and the increase of cortisol levels which we won’t address here due to the depth that would be needed to cover those topics. If you are interested in learning more about how hormones and the keto diet relate to one another, I suggest this article from Dr. Anthony Gustin as a great starting point.

Water and Electrolyte Imbalance

As we discussed in a recent blog post about electrolyte imbalances and their effects on how we feel, we also explained how your body loses stored electrolytes due to increased water, glycogen and electrolyte excretion as insulin levels naturally drop in the absence of carbohydrates.

This depletion of glycogen due to your body producing less insulin is what causes the significant water weight loss typically in the first week or two after going keto, and of course, the by-product of this is the loss of crucial electrolytes that our bodies need to function.

When we lose these key electrolytes like sodium and large amounts of water, it can cause an array of keto flu symptoms like dizziness, headaches, cramping, stomach aches, and nausea.

A great way to avoid feeling like this is to drink plenty of water and consume enough minerals in the food you eat or supplement to make up for the mineral loss.

But What About Things Like Energy Loss and Fatigue?

Fatigue is due to drastically reducing carbohydrates since glucose (sugar) storage easily provides a quick boost of energy when needed so without that glucose store it’s easy to feel more fatigued than usual.

Lets face it, we are all pretty addicted to sugar and its presence in almost everything we eat, whether that’s processed in things like soda or natural sugar in things like fruit.

So, if we make a massive reduction in the amounts of sugar and carbs we eat, we are going to feel the impact negatively at least initially.

Nonetheless, if you are considering jumping in feet first into keto or you are already feeling the adverse effects of the keto flu, here’s what you can do to prevent or reduce your symptoms.

Keto Flu Remedies and Prevention

Drink More Water and Stay Hydrated

keto flu remediesBecause you lose so much water at the beginning of the keto diet, you need to replenish lost water and rehydrate.

Dehydration and mineral loss is the most significant cause of the keto flu, but it can be quickly rectified by drinking more water. Anytime you are feeling nauseous, headaches or fatigued, grab a glass of water.

You can also add some unrefined salt to help replace some of the lost minerals.

Make sure to consume water throughout the day and monitor the color of your urine which is a good indicator of whether you are dehydrated or not. If your urine is bright yellow, you need water, and if it is clear, you are sufficiently hydrated.

KETO TIP: I like to mix a teaspoon of Pink Himalayan salt to my water a few times a week even after being fat adapted for quite some time.

Replenish Electrolytes

There are several ways to replenish your electrolytes. You can increase the amount of salt in your diet which is necessary due to the initial water and sodium loss while adapting to the ketogenic diet.

As mentioned my favorite way is to use Himalayan pink salt either mixed in water or added to my food.

Bone broth can also help, but honestly, it’s usually the salt in the bone broth that is doing the heavy lifting so buying expensive bone broth is not absolutely necessary in my opinion. However, If you love broth, drink up!

Consider eating foods high in potassium such as leafy greens like spinach or swiss-chard, nuts, avocados, clams, and wild-caught salmon.

You can also take an electrolyte supplement that contains magnesium, potassium, and calcium.

Eat More Fats and Calories

While on keto you need to consume more fat for fuel each day. The best way to replace the energy you used to get from carbs and sugar is with healthy fats.

What? Yes, that’s correct. Increasing your consumption of fats can assist in speeding up the transition from burning glucose to burning fat for fuel.

If you’re looking for healthy fats make sure to consider:

  • Avocados and
  • avocado oil
  • Butter
  • Coconut butter
  • Coconut oil
  • Cream
  • Egg yolks
  • Extra virgin olive oil
  • Fatty cuts of red meat
  • Fatty fish
  • Ghee
  • Lard
  • MCT oil
  • Macadamia nuts and macadamia nut oil
  • Fattier nuts, seeds and nut butter (ex. almond and macadamia nuts)

Speaking of MCT oil. Consuming MCTs (medium-chain triglycerides) positively alter your metabolism, are easily burned by the body for energy instead of being stored as fat which can assist ketone production during the keto flu.

Get Plenty of Sleep

Many experts suggest that adults need seven to nine hours of sleep each night. In the real world with family, work and other distractions, that can be tough to do.

Not getting enough rest can cause the stress hormone cortisol to increase, which can make symptoms of the keto flu worse and increase fatigue.

We all know its essential to sleep so try turning off your phone before you go to bed and make changes to your routine to get the rest you need to feel great!

Exercise and Relieve Stress

A great way to increase fat burning and get your body into ketosis faster is to exercise. You don’t need to run a marathon but get out and get moving.

Exercise will help reduce your stress, help you sleep better at night and ultimately help you avoid the keto flu symptoms by getting into ketosis and staying there.

Take An Exogenous Ketone Supplement

Although exogenous ketones are somewhat controversial and are not a replacement for the keto diet, they can help reduce the low carb flu symptoms.

Exogenous ketones add additional ketones to help it become more fat-adapted and enter ketosis more quickly. They can be helpful in preventing or even eliminating keto flu symptoms, boost energy and help fight fatigue by increasing the ketone levels in your system.

If you are interested in exogenous ketones, you can check our supplement recommendations.

The Supplements

keto supplementsBecause the keto diet restricts certain food groups, including fruits and some vegetables, it is a smart choice to include certain key supplements.

Here are half dozen Keto Supplements that you should consider . . .

Vitamin C

Vitamin C helps strengthen the capillaries and cell walls and is crucial for the formation of collagen. It prevents bruising, promotes healing and keeps ligaments, tendons and gums strong and healthy.

It also helps to regenerate Vitamin E so it can be reused and assist the body in absorbing iron from foods. Vitamin C has powerful antioxidant properties.

B-Vitamin Complex Supplement

Vitamin B1

Vitamin B1 (Thiamine) is essential for converting the carbohydrates in food into energy and making the building blocks of DNA as well as making some neurotransmitters. Thiamine levels can be depleted when you drink coffee and tea.

Vitamin B2

Vitamin B2 (Riboflavin) plays a vital role in the production of thyroid hormone, which speeds up metabolism and helps to ensure a steady supply of energy. It also helps the body to produce infection fighting immune cells.

Vitamin B3

Vitamin B3 (Niacin) releases energy from carbohydrates and is involved in controlling blood sugar, keeping the skin healthy and maintaining the nervous and digestive systems.

Vitamin B6

Vitamin B6 (Pyridoxine) performs more than a hundred jobs innumerable times daily. It functions mainly as a co-enzyme to speed up chemical reactions in the cells. It is a water-soluble vitamin and is stored mainly in muscles.

Forming red blood cells, helping cells make proteins, manufacturing brain chemicals such as serotonin and releasing stored energy are just a few of the functions of vitamin B6.

Vitamin B12

Vitamin B12 is essential for cell replication and is important for red blood cell production. It maintains the protective sheath around nerves (myelin), assists in converting food to energy and plays a critical role in the production of DNA and RNA, the genetic material in cells.


Psyllium is a tiny plant seed that is so rich in fiber that it is prescribed for constipation and a wide range of other digestive ailments. The seeds also appear to lower blood cholesterol levels, safely and effectively. Psyllium helps normalize bowel function by absorbing water, so you must stay well hydrated when taking it.

Flaxseed Oil

Both the oil and the seeds from the flax plant are used for therapeutic purposes. Flaxseeds are a potent source of essential fatty acids (EFAs) – fats and oils critical for health than the body cannot make on its own. One EFA, alpha-linolenic acid, is an omega-3 fatty acid. Found in fish and flaxseeds, omega-3 fatty acids have been acclaimed for protecting against heart disease and for treating other ailments.

In addition, flaxseeds are high in fiber and provide substances called lignans, which appear to have beneficial effects on various hormones and may help fight cancer, bacteria, viruses and fungi. Gram for gram, flaxseeds contain up to 800 times the lignans in most other foods.


Creatine is used to produce phosphocreatine, which in turn is used to provide energy to cells. Phosphocreatine is particularly used to provide muscles with energy during high-intensity exercise of short bursts of 15-30 seconds.

Using creatine supplements to increase stores of creatine in muscle may make more energy available to muscle cells when they need it. Creatine can help to increase lean body mass, reduce decreases in muscle strength and reduce cholesterol levels.


Beta-alanine is an amino acid that is used to make carnosine (a dipeptide made from beta-alanine and histidine). Carnosine is an important pH buffer in the muscles – it buffers the acidity (hydrogen ions) produced during high-intensity exercise, thus allowing you to keep going longer and combat fatigue.

Beta-alanine supplementation could be beneficial for activities that last between one and four minutes or involve repeated sprints or surges of power.

Other Keto Side Effects

While the keto diet is generally safe, there are few side effects over and above the keto flu. Let’s take a look at a few of them in this section. Not all of them are bade, but some of them are decidedly unpleasant.

Weight Regain

keto side effects weight regainIf you do the keto diet properly, then you will lose weight rapidly. But some of that weight could come back. Your body will release a lot of water when it starts using fat for energy. This will cause the scale to go down and you will probably appear appreciably leaner. But that initial drop is likely only going to be water weight. That doesn’t mean however, that you haven’t burnt off any fat. While studies have found that you will lose weight on keto, they haven’t figured out if this weight loss is sustainable in the long term.

Most people will find the strict eating plan (i.e. keeping your carbs under 20 grams) a real challenge. If you end up going off the diet, you could conceivably gain all of that weight back again.

Feeling Less Hungry

When you think of a diet, it’s probably associated with depriving yourself of food and feeling more hungry. But that is usually not the case when you follow the keto diet. People who are on keto generally report less hunger and a reduced need to eat. Researchers are not completely sure why this occurs. The belief is that low carb dieters are able to suppress the hormone ghrelin, which controls hunger pangs.

You Will Be Thirstier

When you begin on the keto diet, you will be excreting more water. This is what causes the immediate rapid weight loss. This will make you thirsty. As a result, you should increase your water intake when you begin on keto. Aim for half a gallon of water per day. To gauge if you are drinking enough water, take a look at you your urine. It needs to change from pale yellow to clear.

Positive Side Effects

Your Skin May Clear Up

keto positive side effectAn unexpected benefit of the keto diet for many is that it helps to clear up their pimples. This is especially the case for people who were previously addicted to sugar. The worst thing for acne is empty carbs. That’s because they trigger inflammation. When you drastically reduce your sugar intake, your pimple problems may well take care of themselves.

You Might Have Reduced Brain Fog

Carbohydrates cause blood sugar spikes and dips. So, eating fewer carbs will go a long way to keeping your blood sugar steady. The result will be a more sustained level of energy, fewer sugar cravings and less brain fog.

You Might Have Improved A1C Levels

This one is specific to Type1 Diabetics. Better blood sugar control could help to control your A1C. This is due to better blood sugar control. It could even reduce the need for insulin. On the negative side, a keto diet could also increase your risk of going into ketoacidosis, which is a life-threatening condition. This is more common among people with Type 1 Diabetes. However, Type 2 Diabetics should also consult with their doctor before beginning a keto diet.

You Might Have Low Energy Levels

When you go keto your body is switching over to a whole new fuel source. This transition will involve an adjustment period when your energy levels will be lower than normal. But once your body has adjusted, your energy levels will return to normal.

The Dangers of Keto

The following effects of keto may not be as short term as those in the previous section. These effects are pretty rare, but they could happen.

Low Blood Sugar

low blood sugar in keto dangersThe vast majority of people will experience more stable and lower blood sugar levels. That’s a big part of the reason that low carb diets are effective at controlling Type 2 diabetes. However, one study showed that low carb diets are no better than any other diet. There is also anecdotal evidence that people with Type 2 diabetes were able to stop taking their medicine because they had stabilized their blood sugar. This, though is not recommended. Anyone with diabetes must speak to their doctor before starting keto or any other type of diet.

During the first few days of going keto, your body is still adapting to the changes and is a constant state of change. People with diabetes must ease their way into the diet. You need to slowly cut back on your carbs, which could cause your blood sugar to drop too much.

Nutritional Deficiencies

The high fat, low carb foods that you eat on the keto diet will limit your nutritional choices. It will even eliminate such whole food groups as whole grains, beans and legumes. Many vegetables and fruits are also out. Many of these foods contain important nutrients, including vitamins and minerals. And some of them you can’t get anywhere else.
That’s why the keto diet is not good as a long-term diet – it’s not balanced! If your diet is devoid of fruits and vegetables for too long you will become mineral deficient.

Constipation and Bowel Changes

When you cut of vegetables and fruit, the result will be more than mineral deficiencies. Both fruits and vegetables are fiber rich and fiber helps you to regulate your bowels. Without that fiber, you are likely to experience such bowel changes as difficult bowel movements and constipation.

You can overcome this problem by loading up on fiber rich low carb foods such as cabbage, asparagus and broccoli, along with such fats as ghee and coconut oil. You should also consider taking a fiber supplement, such as psyllium husk.

Loss of Electrolytes

When you are in ketosis, you body will start to dump stores of glycogen, which is found in the muscles and stored fat. This will lead to more frequent trips to the bathroom. It will also lead to the loss of electrolytes. These are important for proper cardiac function and normal heartbeats. It could cause cardiac arrythmia.

As a result, you should try to get more electrolytes through natural sources or over the counter supplements.

Decreased Serum Sodium

Most people consume way too much salt. However, people who are on a ketogenic diet can struggle to get enough salt. Low levels of sodium can lead to confusion, decreased energy, leg cramps and vomiting. That is why, when you’re on keto, you should add salt to all your meals.

The best type of salt to use is Pink Himalayan Salt. It contains 84 minerals and trace elements, including copper, iron, magnesium, calcium and magnesium. Officially classified as halite (rock salt), it is sourced from an area of Pakistan about 190 miles from the Himalayan mountains. The salt deposits in that region are believed to be more than 4 billion years old.


As previously mentioned, when you go into ketosis, you will be flushing water from your body. To help prevent dehydration, try to consume half a gallon of water each day.

Kidney and Kidney Stones

A lack of water can negatively impact upon your kidneys. But that’s not the only way that keto is said to harm your kidneys. Excess protein can create high nitrogen levels. This puts more pressure on the kidneys, which is claimed to lead to kidney stones and damage to your kidney’s cells.

However, recent studies may cast doubt on the concert that too much protein is bad for the liver. The main thing that we use to measure kidney function is creatinine. This is done using a blood creatanine measure. Creatanine is a breakdown product of creatine phosphate in the muscle.

People with more muscle have more creatine in the muscle tissue. They may also have a slightly higher creatanine level in the blood. When creatine phosphate gets broken down, creatine is released. It is then filtered in a part of the kidney and then excreted by the proximal tubial in the kidney.

The blood measure of creatinine can give us an indication of how well the kidneys are functioning. By looking at the blood creatanine concentration, we can work out what is called an EGFR (Estimated Glammacular Filtration Rate). This is the amount of plasma that is being filtered through the glammarius, which are microscopic structures in the kidneys. This gives us an indication of how well the kidneys are working.

Research has shown that people who are on a very high protein diet, such as the caveman diet, do not have any appreciable increase in their blood creatinine levels over the course of the diet.

Another measure of kidney function is cystatin-c testing. This is a measure of body function that doesn’t have so much to do with body composition and muscle tissue. Cystatin-c is a breakdown product of protein that also gets filtered through the glammarius in the kidneys. Unlike creatinine, it doesn’t get secreted in the proximal tubial. But it does have a similar filtration in the glammarius. People with chronic or acute kidney disease will have a rise in cystatin-c levels. Again, people who have been on the carnivore diet in studies have not had an increase in cystatin-c levels.

These results seem to bust the myth that high protein levels are going to damage your kidneys. However, when you eat a high protein diet, the BUN may rise. The BUN is your blood urea nitrogen. This is not an indicator of kidney function as creatinine or cystatin-c are. It is just a by-product of how much protein you are eating and is not harmful. A high BUN has been associated with abnormal kidney function in the past, but it does not indicate kidney dysfunction.

Muscle Loss

The longer you remain in a ketogenic state, the more body fat you will burn. Over time, however, you could also lose muscle tissue. Muscle is, of course, the building block of your muscles. However, your muscles also need carbohydrates for maintenance and formation. In the absence of carbs your muscles could break down.

Cardiac Problems

People who are already on medication for high blood pressure who follow the keto could end up with abnormally low blood pressure. Those who have a pre-existing heart condition should, therefore, consult with their doctor before starting on the keto diet.


Let’s recap what we learned about the Keto Flu and How to cure it

  1. Why the keto flu happens due to transitioning away from carbs and sugar to burning fat for fuel.
  2. The common keto flu symptoms like headaches, fatigue, dizziness, stomach aches, nausea, cramping, and soreness.
  3. The keto flu is temporary and typically lasts a few days to a few weeks at most.
  4. Loss of water and electrolytes contributes to the keto flu.
  5. How to fight off the low carb flu by drinking more water, replacing lost electrolytes, eating more fats, getting plenty of sleep, exercising, relieving stress and considering exogenous ketone supplmentation.

If you want to steer clear of the keto flu or reduce the symptoms make sure to use the tips we’ve suggested above. This will help you make the transition into ketosis and well on your way to the full benefits of the keto diet once you are fat adapted.

If you are new to keto or just want to get a more in depth overview of the ketogenic diet make sure to read our comprehensive Keto Diet Guide.

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