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The Keto Flu: Full Diagnosis and Cure

The Keto Flu: Full Diagnosis and Cure

What is Keto Flu?

Did you start keto a few days ago and can’t stop feeling nauseous and tired? That is because you’ve got the keto flu. Don’t worry it isn’t contagious or dangerous and will get solved on its own. All you have to do is continue the ketogenic diet, so you enter ketosis and your body starts burning fat.

Keto flu usually lasts for up to five days, but if you hold onto it longer, you will experience the symptoms for over a week. Your body’s carbohydrate withdrawal causes the symptoms. Keto diet is a great way to lose fat without doing much exercise. A recent found that carbohydrates, especially simple sugars, has cocaine-like effects on the brain, which means your brain gets addicted to it and the carbohydrate withdrawal symptoms indicate that your body is transitioning to use fat as the primary source of energy. [1]

If you allow the symptoms to get the better of you and binge eat carbohydrates, you will have to start keto again and experience all those symptoms again as well. It commonly happens among short-sighted people. Once you adjust to consuming only 50 grams of net carbohydrates in a day, you will realize that you never needed to consume over 400 to 500 grams of net carbs daily.

What are the symptoms?

Keto flu is a sign of your body starting to adapt to extremely low carbohydrate intake. So, it is obvious that your body will show some symptoms of the change, which are often uncomfortable. While some people the transition is very difficult and tormenting, others barely experience anything other than slight tiredness.

Also, different people experience different levels of symptoms from mild to strong. Let’s take a look at the symptoms of keto flu:


1. Nausea

2. Constipation or diarrhea

3. Brain fog

4. Confusion

5. Lack of concentration

6. Muscle soreness

7. Irritability

8. Extreme sugar cravings

9. Stomach pain

10. Headache

11. Vomiting


Even though there are a lot of symptoms, most people don’t experience more than one or two. The symptoms have differing intensity through the day, so you can get all work done when you feel good and relax when they get the better of you. It is worst in people who get it immediately after starting the keto diet.

Understanding the Different Keto Symptoms

To understand the symptoms better, we need to know why the symptoms occur in the first place. Let’s take a look at the three main causes of keto flu:

1. Increased levels of cortisol

When you enter ketosis, you enter a phase of starvation. Your body is alerted that there is a lack of carbs circulating the blood. As a response to the restriction, your body releases cortisol, one of the most common stress hormones. In a study conducted on men, it was revealed that men who consume a high carbohydrate diet have higher testosterone levels and low cortisol levels. It was the opposite in men who consumed a low carbs diet. They were divided into two groups - 60 percent carbs and 30 percent carbs. It concludes that by decreasing carbs even by 10 percent increases the cortisol levels. [2]

cortisol level keto

It is what makes insomnia one of the main symptoms of the keto flu. Increased cortisol levels also make you more irritable. However, once you are out of this stage of ketosis, the cortisol levels will stabilize and everything will get back to normal.

2. Decreased T3 levels

Production of T3 thyroid hormone levels is directly linked to the consumption of carbohydrates. During the study, a group of people were put on a zero carb diet. They showed a 47 percent decrease in T3 thyroid hormone levels. T3 is around five times more efficient than T4, which is synthesized in higher amounts in our bodies. When T3 levels decrease, reverse T3 levels increase, which is something to be avoided at all costs, but it is impossible with ketosis. The study divided obese people in eight equal groups. Each were given different amounts of carbohydrates.

The researchers found that only when daily carbs consumption was reduced to 120 net grams or below, the T3 levels decreased. Reverse T3 levels rose only when the person consumed around 40 to 50 grams of net carbs daily. [3] Low T3 levels make your lethargic and can cause extreme sugar cravings. It also leads to increased stress levels, which can further boost cortisol production.

3. Water and sodium imbalance

Carbs soak up water, which sometimes leads to bloating. When you restrict net carbs to only 50 grams a day, your body rapidly starts using the stored carbohydrates. This breaks the water held in the molecules and is lost via urination. The insulin level drops around the same time and your body starts losing sodium as well. This is the reason why you lose rapid weight in the beginning of ketosis as you lose up to 10 pounds of water weight in just a couple weeks or less.

Another two pounds come from the glycogen stores of the liver and muscles. You tend to experience dizziness, cramping, constipation, and diarrhea because of the sodium imbalance. The loss of water causes brain fog and lack of concentration.

Why do some people get it?

Knowing all that we talked until now would have made you question why some people experience keto flu and others don’t. The single most reason behind it is metabolic flexibility. It is the adaptive capacity of a person to adapt to a different type of fuel oxidation depending on the type of fuel available.

There are two factors that make a person metabolic flexible. These include:

1. Lifestyle

If you tend to eat out a lot or eat high sugar foods on a regular basis, you are going to find it difficult to switch from carbohydrate to fat as the major energy source. When you switch to a keto diet, the carbs consumption reduces to only 50 grams of net carbs in a day, which is like a shock to your body. On the other hand, if you are someone who keeps away from simple sugars and consumes low carbs otherwise as well, you will only experience mild symptoms or none at all.

2. Genetics

When we talk about genetics, we are talking about the digestive enzymes. If you have low fat-digestive enzymes, you won’t be as metabolically flexible as someone who has a strong combination of digestive enzymes. These enzymes help people to switch to fat as energy source almost immediately.

Ketosis is similar to exercise. People who have an active lifestyle find it easy to adapt to exercise, while those who live a relatively sedentary life seem to have it difficult. Also, there are more factors that play a role in a person’s metabolic flexibility but they can’t be determined as they are very specific to the individual and needs to be studied more.

How long does it last?

Keto flu lasts for around three to five days in people who catch the symptoms and start taking curative measures. For those who continue not drinking enough water or consuming enough sodium, the effects will continue for at least two weeks and force you to give up on the keto diet. The symptoms during this time are extreme causing you to not concentrate on work at all.

How to cure the Keto Flu?

To cure the keto flu, you need to make changes in your diet and lifestyle. They are small changes but have a huge impact on curing the terrible symptoms.

1. Balance the electrolytes

People who aren’t on a diet are recommended to consume no more than three to four grams of salt per day but on ketosis, you can consume up to seven grams of water. It is around one and a half teaspoons of sugar. Add salt as you do in your food but also sprinkle a little on the top while eating it. You can also consume naturally-occurring high sodium foods like fish, bacon and different types of meat products, cottage cheese, and salad dressing.

Potassium and magnesium also help in balancing the electrolytes. High potassium foods that you need to consume to get to the ketosis flu symptoms include spinach, mushrooms, cucumber, and avocado. You can also consume Potassium Gluconate supplement, which is easily available in any supermarket or grocery store.

Magnesium isn’t an electrolyte but acts as a stabilizer during your ketosis transition. It not only treats cramps, but also prevents them from occurring. It also helps in improving sleep quality and insulin stability. Rich sources of magnesium that you can consume on a keto diet include spinach, pumpkin seeds, and raspberries.

2. Drink plenty water

You lose mental imbalance when you lose two percent of body water. When it reduces by 2.8 percent, cognitive function gets impaired. You tend to lose around two to three percent on water during the first two weeks of ketosis. To avoid the symptoms, you need to consume increased amounts of water with added salt.

An adult man should drink at least 3.7 liters of water daily, while an adult woman should consume a minimum of 2.7 liters of water daily during a keto diet. Remember, these are the minimum quantities. The more you consume, the less symptoms you experience.

3. Meditate regularly

When you feel stressed, you meditate, which helps to release feel good hormones. It is the same with ketosis-induced cortisol production. Sit quietly for 15 minutes every day and relax. You don’t need to think about anything. Close your eyes and perform a couple breathing exercises. Meditating will help you relax and reduce the cortisol levels. It will also help you regain the concentration and focus.

If you think, you need something more, you can download one of those meditation apps that help you relax. There are a lot of white noise videos available on YouTube. You can make a playlist of 15 minutes combined and listen to them. Fix a time during which you will meditate daily so that you develop a pattern that helps you relax.


4. Consume more MCTs

Medium chain triglycerides is a type of fat that is easily converted to energy by our bodies. Coconut oil and palm oil contains the highest amount of MCTs. Thanks to technology, you can readily buy MCT oil from the supermarket and use it for cooking. The oil goes directly to the gut, where it is digested by the gut microorganism and digested. It is then transported to the liver where it gets converted into keto, which is then used as an energy source.

Other types of oil enter a long process of digestion in the small intestine, which is a much slower and longer process. The end product in the small intestine is chylomicron, which enters the lymphatic system and then transported to the respective body parts and organs. You can also use it as a part of the salad dressing.

5. Take exogenous ketones

If you want to speed up the ketosis process, consume exogenous ketones as it helps the body to adapt to change in energy source. It is available as ketone salts, which can be consumed as a supplement. Consume ½ scoop of ketone salts once a day for three to five days from the onset of keto flu. If you want to exclusively start losing fat immediately after you start the ketogenic diet, you should consume one scoop of ketone salts mixed in water daily.

Many people find it difficult to concentrate for longer hours when on a keto diet and that is because your brain isn’t receiving enough carbohydrates as only simple sugars can cross the blood-brain barrier. Only small amounts of ketones can travel across but the quantity isn’t enough. To regain longer concentration, you can consume ketone salts in the same amounts mentioned above on empty stomach.

6. Indulge in light exercises

Go for a quick walk in the morning after you wake up. Remember to take a bottle of water with a pinch of salt mixed in it. Make sure you drink water at regular intervals. Your aim should be to walk for at least an hour but you can start with 15 minutes and increase the duration. The more you walk, the more you will start feeling better and the symptoms of ketosis flu will be minimal.

It is all a great change to your lifestyle and you will fall in a healthy habit to stay active. You don’t need to go running or hit the gym and lift weights because the ketogenic diet will help you in losing weight. The walk will keep up your metabolism making the transitioning easy.

Keto exercise

7. Sleep well

The key is to let your body relax and cope up with the transition. When you sleep adequately, you are less irritable and will experience the symptoms in a lower intensity. You should get at least seven to nine hours of sleep every night and if you feel drowsy or less energetic in the middle of the day, take a quick 30 minutes nap.

Take magnesium supplements an hour before going to bed. You will get a deep and undisturbed sleep and help you fall asleep faster. You can also dim all lights and create a sleepy atmosphere to help you as dull yellow lights help in melatonin production. It is secreted by the pineal gland of your brain. Avoid taking melatonin supplements or sleep medicine because they have negative effects on the kidney and also make you dizzy all day long.

8. Don’t cut down on calories

Don’t go a calorie-restrictive diet when on ketosis. Restricting calories will only make you dull and deprive you of all the required nutrients. Also, make sure that you don’t eat too much protein as a part of your keto diet because it will make you feel nauseous. Eat only a small amount of protein, which offers concentrated nutrition including egg, fatty fish, beef, and pork.

If you eat too much protein, your body will stabilize and not use fat as the main fuel. Instead, it will start using protein, some of which are glucogenic and can be converted into glucose. It defeats the whole purpose of doing a ketogenic diet.

keto macros nutrients

9. Transition diet

If none of the cures mentioned above work for you, it is an indication that your body isn’t ready for a keto diet. But that doesn’t mean you will never be able to do ketosis. Take it slow. Start with a low-carb diet, in which you only consume 40 percent of total calories as carbs. Every week, deduct five percent until you reach 50 grams of net carbs a day.

If you think you can handle going below 50 grams, you can do try up to 20 grams of net carbs a day. At this point, the weight loss will be very rapid, so ensure you keep yourself hydrated and don’t give up. The weight loss will be progressive and not as rapid as it is on a ketogenic diet but you won’t experience any of the symptoms.

How to prevent when starting Keto Diet?

It goes without saying that prevention is better than cure. Keto flu is something you can absolutely avoid. Let’s take a look at a three-step approach to prevent the keto flu:

1. Concentrate on the nutrients

You can simply consume cheese and meet your daily macronutrient requirements but that will make you deficient in several micronutrients. Since you can’t consume most of the fruits, you are going to be lacking in water-soluble vitamins like Vitamin C and B complex. You can eat berries, so grab a couple strawberries or five to six raspberries and blueberries with every meal.

It is also crucial to avoid unhealthy foods like fried food during the first two weeks. Once you get into a keto diet routine, you will rarely get carbs cravings, which you can fulfill on your cheat day.

macronutrients keto flu

2. Sleep well

Getting adequate sleep is a prevention as well as a cure. Due to the shift in major energy source, your body will need some pampering. Apart from getting seven to nine hours of sleep, take extra long hot showers or treat yourself with bubble bath every now and then.

Concentrate on your skincare and body care routine so that you have less trouble sleeping. If you find it difficult to sleep for long hours during the night, you can take one or two 30 minutes nap during the day. Once you are in ketosis and feel that your body can handle five to six hours of sleep in the night, you can cut down the afternoon naps. However, if you think your body needs those power naps, accept it and sleep. It will help to remain focused and productive at work.

3. Take proper supplements

Many people think that their ketogenic diet is full of nutrients, macro and micro, and take pride in not taking supplements. Since your body isn’t receiving all nutrients proportionately, you tend to suffer from keto flu. Here is a list of supplements you need to take as a part of your keto diet:

    1. Exogenous ketone salts

Taking exogenous ketone salts helps in entering ketosis faster than the body usually does and is very instrumental in avoiding the keto flu. They also decrease appetite, so you will able to avert carbs cravings easily.

    2. Multivitamins

Since you get fat-soluble vitamins from your fat-rich diet, you have to only concentrate on water-soluble vitamins. Vitamin C and B complex are available mostly in capsule form, which you should take before lunch or dinner. One capsule a day would be enough. You can take one more daily if you are feeling particularly lethargic or coming down with a cold.

supplements keto diet

    3. Calcium and vitamin D

You cannot have milk during a keto diet. You can have cheese and yogurt but that isn’t enough to meet your daily calcium requirements. Take a calcium and vitamin D tablet once a day before breakfast as absorption is maximum on an empty stomach. Vitamin D helps in faster absorption of calcium and also helps in weight loss by preventing hormone imbalance.

    4. MCT oil

Make MCT oil a part of your day. 25 percent of your daily requirements can be MCT oil so that your body easily transforms into ketosis. You can reduce it to only a couple tablespoons after a month. You can either add it to keto coffee, shakes and smoothies, or drink it directly using a spoon. It is tasteless, odorless, and has a smooth texture, so you won’t have any problems in gulping it down directly.

    5. Magnesium

Magnesium is a wonder mineral that helps in calcium absorption and melatonin production so that you fall asleep with little difficulty. Take one tablet a day around one hour before you go to sleep.

    6. Digestive enzymes

You will digestive enzymes to manage the change in primary energy source. Like we mentioned earlier, lower amount of digestive enzymes can give you a keto flu because your body needs more time to adjust to the changes. When you take digestive enzymes, your body has everything it requires to help in fat digestion. If you don’t take digestive enzymes and have a low count as well, you will tend to experience gastrointestinal troubles like nausea, bloating, diarrhea, or constipation.

These digestive enzymes are usually a mix of proteolytic (protein-breaking) and lipolytic (fat-breaking) enzymes. You can blend a serving of digestive enzymes with your smoothie or simply pop a capsule 30 minutes after having lunch and dinner. You can start with two capsules a day and reduce it to once you have passed the phase.

    7. Dietary fibers

With only 50 grams of net carbs meeting your daily dietary fiber needs seems impossible. There are basically two types of dietary fibers, which include soluble and insoluble fiber. Humans cannot digest both types of fibers and each play a huge role in maintaining gut health. Soluble fiber can be fermented partially by the gut bacteria to release MCTs, which are called energy bombs as they release huge amounts of energy and are easily digestible.

Dietary fiber is further divided into insulin, methyl-cellulose, wheat dextrin, and psyllium. All of them are easily available online or in supermarkets either in powder or capsule form. Start with consuming one tablet after lunch and dinner. If you want to use fiber powder, you can add it to your cooking. It doesn’t taste anything but will give your food a gelatinous consistency.

    8. Chlorella

Chlorella is a type of single-celled algae that helps in maintaining energy levels during the first weeks of a ketogenic diet. The tablet is a rich source of Chlorella Growth Factor, which is found in chlorella DNA and RNA. It helps in regeneration and transport of energy in an efficient manner so that minimum amounts are lost during its transportation.

Make sure you buy chlorella supplementation that has been tested for and cleared heavy metal contamination tests. It is available in capsules, tablets, granular, and powder form. You can use whichever seems comfortable. Take one serving daily after a mid-morning snack to feel energized throughout the day.

    9. Green tea and black coffee

Green tea is abundant in catechins that helps in boosting the immune system. Two cups of green tea a day with some berries will make you feel rejuvenated and keep away the illnesses. Black coffee, on the other hand, gives a boost of energy and also burns fat. Keep at least two hours difference between the two drinks because they have relatively differing uses.

You can have one cup of green tea in the night with a tablet of magnesium to relax your body and prepare for sleep.

tea coffee keto flu

    10. L-glutamine

You might have seen many fitness geeks promote and use L-glutamine supplements. It is an antioxidant that you take immediately after working out. Your body is in a state of trauma when you are transitioning as the cortisol levels are high. There is going to be a lot of free radicals production and L-glutamine being an antioxidant will help neutralize them. One serving in water after your morning walk or light exercise session will work out just fine.


Keto flu is completely avoidable. Take all precautionary measures and use our guides to educate yourself about ketogenic diet before you start it. Weight loss on ketosis is rapid, so make sure you rest well and don’t jump on the weighing scale every now and then because it will leave you disappointed.




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