Help I feel like death, what is the carb flu aka keto flu?
Carb withdrawal or “carb flu” often also known as “keto flu” is a label given to a set of carbohydrate withdrawal symptoms that may occur in people who start following a low carb diet.

It is the result of altered hormonal states and the electrolyte imbalances that may occur with it. In other words, it describes a cycle in the body adapting to a newly started low carb diet or keto diet.
Keto stands for ketogenic, a very strict low carb eating plan. The term should really be “low carb flu” since the ketogenic diet is not the only low carb plan.
The carb flu can occur whether you cut your carbohydrate intake moderately or severely and everyone’s severity will be different depending on their current carbohydrate intake.
Just a reminder that I’m not a doctor or medical professional I’m just sharing my personal journey and what I’ve done. Always talk to your doctor!
By continuing to read, access and use this website, Ketovorish, you agree to be bound by the terms and conditions. As with any dietary change, care and precaution should always be taken. If you have any medical conditions, medications or health concerns that require monitoring/discussing, you must be under the supervision of your regular health care provider who can monitor you with any dietary change. This is not a suggested diet, just my personal experiences.
Can cutting carbs make you sick?
When you cut out or lower your carbohydrate intake your body will have to shift to source energy from other stored sources, like fat or protein.
There can be a delay as the body shifts metabolic processes to generate glucose from the liver or from stored fat. How long it takes for your body to transition will vary depending on individual circumstances
In the meantime, it’s not unexpected that you may struggle with irritability, fatigue, and otherwise feeling lethargic and tired. While cutting carbs won’t give you a viral infection like the flu, it can make you feel pretty terrible in the short term.
Symptoms of Carb Withdrawal List
No two individuals are alike, so the carb detox symptoms can range from nothing to mild to a full-blown flu-like condition. The following are the most common reported symptoms:
- Lightheadedness
- Nausea/vomiting/upset tummy
- Fatigue/weakness
- Mental fog
- Poor concentration
- Irritability
- Muscle cramps
- Headaches
- Diarrhea/constipation
- In some extreme cases, high blood pressure and arrhythmia
- Sugar cravings
- Trouble with sleep

How Long Does Keto Flu / Carb Flu Last?
The duration of carb withdrawals varies for each person. While some may have slight and even unnoticeable symptoms for a day or two, others might have what seems like over the top symptoms for a week or more, it really depends on how quickly your body adapts to a reduction in carbs.
Once carb flu is over you can usually expect a huge surge in energy levels, and once that sugar habit is fully kicked, often people feel better than ever.
Being patient as your body adapts is key, and know that it will pass, and if it does not you should seek the attention of a qualified medical professional.
For most people any carb withdrawal symptoms that occur end within two weeks’ time.
When the Going Gets Tough…
People who experience keto flu after going on a low carb or keto diet are sometimes forced to believe that they are suffering due to the diet they are on and carbs are good for their health after all.
However, this only shows how dependent they have been on carbs, as their body is trying to survive (which we can absolutely do) without carbs and sugary substances.
In truth, carb intake, and especially refined carbs that come from processed food, sugar, sugary foods and drinks is at epidemic levels, and carb addiction is rampant in the United States and other parts of the world.
It’s not your fault, those carbs are everywhere, congratulate yourself on making changes for the better with a low carb diet!
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Keto Flu Relief
Carb or keto flu can be nerve wracking. Unfortunately it is also sometimes a necessary evil. However, don’t despair as there are some things that can be done to reduce the symptoms if they appear.
Drink water. Reducing your carbs can cause you to rapidly shed water stores as the kidneys ramp up their role in reducing your glycogen stores.
Replenish your electrolytes: Lack of electrolytes in the body is one of the major causes of carb flu. Electrolytes are the minerals found in the body and they affect water content, acidity of the blood and functionality of the muscles.
Additionally, low carb and keto diets lower insulin levels that can signal the kidneys to discard excess water, making you drink more and this results in flushing out electrolytes – this is where sodium, potassium and magnesium deficiencies can occur. You may have to replenish them by using supplements and with food.
- Add in some salt: Normally, the average diet is overloaded with salt, but a ketogenic diet eliminates refined and processed food and focuses on eating whole real food so when you start low carb you will naturally reduce salt intake, which reduces water retention. Since a low carb diet is naturally diuretic, there is no need to worry about water retention.
Generally, 5 grams of salt daily is ideal for keto flu and to replenish electrolytes, you can also get it from drinking bone broth or even adding soy sauce and other sauces that have potassium to your meals.
Bone broth works well, and only requires the simmering of chicken, beef, lamb or any meat bones in water for about a day, or even canned broth or stocks from the store works well too, just make sure to read the labels for added ingredients or preservatives that you do not need. Drippings from cooked meat have a high concentration of potassium, so use them to make sauces.
You can also use electrolyte powder drinks if you prefer.
- Magnesium can be taken in supplement form.
Magnesium is a great supplement for helping with many of symptoms of carb withdrawals including muscle cramping, headaches and fatigue. Lack of magnesium can also cause an abnormally fast heartbeat (heart arrhythmia) which is also a symptom of carb flu.
When starting a low-carb diet, magnesium is not depleted as much as sodium. However, some people experience leg cramps at night and during exercise while eating low-carb. Magnesium supplementation (and potassium) can relieve the cramping.
If you haven’t been scared away yet you can read about the 7 Stages of Carb Withdrawals for more tips an how to survive carb flu.
Please contact a doctor if the symptoms become too severe to handle alone.
References:
https://www.healthline.com/nutrition/keto-flu-symptoms
https://pursuit.unimelb.edu.au/articles/drop-the-sugar-coating
https://pubmed.ncbi.nlm.nih.gov/18828029/ Estimating changes in hydration status from changes in body mass: considerations regarding metabolic water and glycogen storage