How to Avoid Keto Flu & Keto Flu Remedy Tips

Kiah Connolly, MD

Increased talk about avoiding and curing the keto flu has surged with the recent rise of the keto diet.

But what exactly is the keto flu? Is it avoidable? What does it encompass?

It sounds like a disease - is it contagious?

What is the Keto Flu?

Dieting isn’t easy! But can certain diets make weight loss easier?

The goal of the ketogenic diet is to transition the body into a metabolic state called ketosis through significant carbohydrate restriction. While in ketosis the body can primarily utilize fat for its source of fuel and in theory be more efficient at losing weight.  

If you want to learn more about the ketogenic diet, reading this article is a great place to start.  

Keto flu describes unpleasant symptoms many people experience during significant carbohydrate restriction required by the keto diet.

While it isn’t life threatening or dangerous, it can make many people feel awful.

We are biologically built to love and crave carbohydrates. This is largely because these delicious carbs are quickly broken down into glucose - which is the most accessible energy source we can use.

So what happens when we don’t let our body have what it wants? Well, it can put up a bit of a fight - and sometimes throw a tantrum.

Keto Flu Symptoms

No, it’s not actually a disease. And no, it’s not contagious. But, keto flu can feel damning nonetheless.

Even worse, the keto flu, unfortunately, discourages many people from continuing their keto diet journey. Because all of our metabolisms can behave just a little bit differently, the symptoms and the severity of symptoms experienced can be unique to each individual.

So what are the most common keto flu symptoms?

  1. Hunger
  2. Fatigue
  3. Mood Changes & Irritability
  4. Decreased Libido
  5. Dizziness
  6. Decreased Concentration & Brain Fog
  7. Headaches
  8. Bad Breath
  9. Insomnia
  10. Constipation
  11. Muscle Aches

The important thing to remember is that the side effects from starting the keto diet are temporary! Many people that push through this phase report feeling better than they ever have in ketosis.

Keto Flu Avoidance & Recovery Tips: How to Keep Away from the Keto Flu

What can you do to fight and prevent the keto flu? 

1. Drink Water

As explained in more detail below, your body may be more susceptible to dehydration on the keto diet -- and dehydration can contribute to keto flu symptoms, especially headache, nausea, lightheadedness, constipation, and difficulty concentrating. Drinking more fluids including water and no-calorie flavored water can also help you feel more full, leaving you more satiated and less hungry (1, 2).

2. Sleep

It’s expected to experience a temporary decrease in energy and fatigue when starting the keto diet. You’re literally putting yourself through major metabolic changes. Your body’s response to decreased glucose intake is what triggers it to transition into a state of ketosis. It’s natural that during this process your energy levels feel lower - because they are.  Schedule additional time for yourself to rest while these changes take place.

Whether you’re in ketosis or not, getting adequate sleep has also been shown to lead to less cravings throughout the day which is always a positive boost for your weight loss goals (3) .

So do what’s right for your body and let yourself snooze.

3. Eat Keto Approved Foods (A LOT) 

While calories are undeniably a tremendous influence on health and weight loss, some people advocate that you don’t need to worry about these on the keto diet. While this is one way of doing things, and may sometimes lead to weight loss - it’s also completely dependent on the number of calories one consumes. Eating an overwhelming number of calories more than what you burn will still lead to weight gain - regardless of whether or not you’ve gone keto.

However, you may feel particularly hungry and have strong cravings for carbohydrates when you first begin the ketogenic diet. Trying to be too strict with yourself all at once can lead to you being more susceptible to breaking your diet and overeating on the wrong foods.

So, while we do recommend to consider calories on your overall keto plan it may be beneficial to allow yourself an adjustment period on the keto diet. During this time you can focus mainly on following the macronutrients recommended by the diet without honing in too much on calorie consumption. When you are hungry  (or just have intense cravings for carbs) try eating more keto approved foods to help satisfy your needs. Over time, these will become less as your body adjusts and you can begin focussing more on incorporating your calorie goals.

4. Eat Salt

As explained in more detail below, the keto diet may contribute to you losing some salt as well as to dehydration. Replacing this salt may improve your symptoms, and when paired with active oral hydration can also help your body to more effectively retain fluids you’re drinking. It can also help you to feel more full and contribute to you eating fewer calories or craving non-keto foods throughout the day.

If you’re on a low salt diet for hypertension, congestive heart failure (CHF) or any other medical condition, it’s very important that you talk to your doctor for formal medical recommendations before changing your prescribed diet. 

5. Meditate

Meditation offers a  slew of benefits for the mind, body, and soul. On the weight loss front, it’s been shown to be beneficial for binge and emotional eating as well as weight loss maintenance in obese individuals (4, 5, 6). It also offers to decrease anxiety, improve mood, and concentration. Other studies link meditation to improved heart health which is possibly due to a decrease in stress hormones in those that meditate (7).

Whatever is happening with mediation seems powerfully positive.


Who Will Get the Keto Flu?

The process of transitioning into ketosis can affect everyone differently. Some don’t notice much change and report feeling at their best on the keto diet almost immediately - while others feel wretched for weeks. There, unfortunately, isn’t a good way to know how you’ll feel on a very low carbohydrate diet until you try it.

When Does the Keto Flu Start?

Symptoms of the keto flu often start 24-48 hours of following the keto diet. This can vary for some, however, it usually doesn’t start after more than 7 days of strict adherence to the diet.

What does this mean? If you’re still feeling good by the end of the first week, you’ve likely avoided the keto flu all together!

How Long Does Keto Flu Last?

Once you’ve been hit with the keto flu, symptoms often resolve in the first couple weeks. However, it can last up to one month.  

So what exactly is it about this diet that’s causing so many people to feel miserable? Let’s take a quick look at the theories behind the causes of the keto flu.


What Causes the Keto Flu?

The medical community really can’t yet say for sure exactly what causes the keto flu - but we do have some educated guesses.

The main theories behind what causes the keto flu include:

  1. Hypoglycemia
  2. Carbohydrate Withdrawal
  3. Hormone Imbalance
  4. Electrolyte Imbalance
  5. Dehydration

In reality, each individual may have symptoms due to one or a combination of these factors.

1. Hypoglycemia

Carbohydrates quickly break down in your body to glucose. Your body regularly uses energy from stored glucose through a process called glycolysis - it almost always prefers this process. When you cut out carbohydrates, your body is forced to transitions from using glucose to using fat for energy through a process called beta-oxidation and production of ketone bodies.

It’s harder and takes more time to use fat for energy. Therefore as the body is in a transition phase from using glucose to using fat for fuel, blood glucose can be low - called hypoglycemia. Hypoglycemia alone can cause many of the symptoms described by the keto flu. And while most of our bodies can compensate to ensure we maintain safe levels of glucose, this can be a dangerous condition in people with type 1 diabetes or anyone on medication for diabetes.

2. Carbohydrate Withdrawal

Some science suggests that many of us may actually be physically addicted to carbohydrates.

Many people experience the same process of binging, withdrawal, craving, sensitization and overall dependence on sugar as is seen with other forms of addiction, such as alcohol. Literally the same areas of the brain that light up with drug addictions similarly light up when people eat carbohydrates. Neurotransmitters in the brain strongly associated with addictions, such as dopamine are also released when eating carbs (8, 9).

Classic symptoms of a variety of drug withdrawals often involve irritability and other mood changes, nausea, lightheadedness, headaches, difficulty concentrating. Sound familiar?

Could keto flu just be our response to withdrawing from carbohydrates (ie: sugars)?

sugar resized 

3. Hormone Imbalance

There are some theories that thyroid hormones can also be temporarily altered with carbohydrate restriction. Lower levels of T3 - an active thyroid hormone in your blood - can lead to many symptoms including fatigue, constipation, mood changes. While this is one theory that exists as a possible contributing factor to the keto flu, there really hasn’t been enough evidence to link low carbohydrate intake to subclinical hypothyroidism (10). 

5. Dehydration & Electrolyte Abnormalities

Insulin is the hormone in charge of storing glucose. In order to maintain a steady state of glucose in the body, insulin rises when carbohydrates are consumed and maintains lower levels during times of fasting. When carbohydrates are not consumed, insulin does not rise as high after eating because there just isn’t as much glucose to store.

Because it can also affect the absorption and availability of water and electrolytes lower levels of insulin can contribute to changes in electrolytes in our body and dehydration. So transitioning into ketosis can encourage diuresis - a process where you lose sodium and water (11). Usually, these levels aren’t dangerous, but they can definitely contribute to feeling bad.

Staying hydrated and eating higher sodium contents may help improve keto flu symptoms.

Other Keto Diet Risks & Cautions

The keto diet is largely regarded as safe in both children and adults. Because it was originally utilized to help prevent seizures in children with epilepsy it has been extensively studied and shown to be safe even in this population (11). However, the keto diet is probably still not a good choice for some people.

Keto Diet in Pregnancy

Pregnant and breastfeeding women should probably not be following a ketogenic diet due to their increased glucose needs to support their pregnancy.

Sustaining extremely low levels of carbohydrates can be dangerous for pregnancy. 

It is generally recommended anyone pregnant or breastfeeding consume at least 50 grams of carbohydrates daily (12).

Keto Diet in People with Kidney Problems

People with renal disease (anyone on dialysis and other individuals with a consistently elevated creatinine) are probably not a good fit for the traditional keto diet. Because the kidneys are in charge of processing much of the protein we eat, the moderate to high protein intake recommended in the keto diet has the potential to be dangerous for people with kidneys that do not function properly (13). Make sure to talk to your doctor before starting the keto diet if you are unsure if your kidneys are functioning well.

Keto Diet in Diabetes

This is probably not the best diet for people with type 1 diabetes as they have a much higher risk of developing a dangerous condition called diabetic ketoacidosis as well as hypoglycemia. However, some type 1 diabetics committed to the keto diet lifestyle can enjoy success provided extremely careful blood glucose monitoring and working closely with their doctor for frequent medication adjustments.

On the contrary, the ketogenic diet may be ideal for people with type 2 diabetes as it may contribute to fast weight loss and improve insulin sensitivity while maintaining a low and steady carbohydrate intake.

However, advanced type 2 diabetics on insulin and oral medications still have an increased risk of developing hypoglycemia and diabetic ketoacidosis. It is therefore extremely important all diabetics taking medications to work closely with their doctors prior to and throughout the course on the keto diet as more frequent blood glucose checks and medication adjustments may be necessary.

To learn more about the keto diet in diabetics read this: Keto Diet for Diabetics: 3 ways the Keto Diet Could Cure Type 2 Diabetes.

Why Try the Ketogenic Diet?

All the dieting rage right now seems centered around the ketogenic diet. But why would anyone want to try the keto diet after hearing so many awful things about the keto flu?

Many claim that this diet has the power to simultaneously suppress our appetite and to most effectively make us lose weight.


Doesn’t this theory sound great? If ketosis makes our body burn fat for energy and stops us from being hungry - shouldn’t we just get ourselves into this state of ketosis and let it melt all of our fat away?

Well, maybe. But in the grand scheme of things there just haven’t been very many well-done studies in people evaluating the ketogenic diet for weight loss to prove these theories actually work.

As mentioned above, this diet was actually originally validated as a treatment for seizures in children. While this may seem like random application, the diet alone has been shown to be very effective for many individuals with seizures. What’s more, these extensive studies have shown it is safe in even a pediatric population.

But what about weight loss?

More studies recently have started looking at the keto diets potential for weight loss, and many are promising. To learn more about current research available on the ketogenic diet for weight loss read this article

Looking for a Keto Meal Delivery Service? Try Trifecta: fully cooked, organic, keto meals delivered to your doorstep.


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