Table of ContentsView AllTable of ContentsDefinition and SymptomsWhy It HappensIs It a Sign of Ketoacidosis?How to Get Rid of ItWho Gets It?Symptom DurationWho Should Avoid Keto?Seeking Medical Care
Table of ContentsView All
View All
Table of Contents
Definition and Symptoms
Why It Happens
Is It a Sign of Ketoacidosis?
How to Get Rid of It
Who Gets It?
Symptom Duration
Who Should Avoid Keto?
Seeking Medical Care
People who adopt a ketogenic (keto) diet may experience minor, short-term symptoms like nausea, fatigue, and headaches when starting the diet as the body enters a metabolic state calledketosis. The short-term symptoms of the keto diet result when the low-carbohydrate (low-carb) eating plan forces the body to burn fats rather than carbs for energy. Symptoms signify keto induction, which is often referred to as “the keto flu.”
This article covers ways to manage or prevent the keto flu if you adopt a keto diet.
nensuria / Getty Images
How Long It Takes to Enter Ketosis
What Is the Keto Flu Exactly?
The keto flu is a collection of symptoms you may experience when starting the keto diet as your body adjusts to a drastic reduction in carbohydrate intake. Adopting a keto diet can lead to different symptoms for everyone, but some common signs that you may be experiencing keto flu include:
These symptoms result from your body switching from using glucose (sugar) as its primary energy source to burning fat for fuel, which produces compounds called ketones.
Why Does the Keto Flu Happen?
When your body shifts from glucose to fat as the primary fuel source, it can lead to a temporary electrolyte imbalance that triggers dehydration, the primary cause of flu-like symptoms. While the keto flu typically lasts afew days to a week, staying hydrated, replenishing electrolytes, and gradually reducing carbohydrate intake (versus cutting them too quickly) can help minimize these side effects.
Is the Keto Flu a Sign of Ketoacidosis?
Given their similar names, keto flu and ketoacidosis are often confused. However, these are two distinct conditions, as follows:
How to Get Rid of the Keto Flu
To alleviate symptoms of the keto flu, stay well-hydrated and eat a variety of nutrient-rich foods that can help maintain your sodium, potassium, and magnesium needs. Slowing down how quickly you cut carb intake can also help your body adjust more smoothly. Finally, get plenty of rest and enjoy light exercise to support your body and overall health during the transition.
Stay Hydrated
Staying hydrated helps maintain properelectrolyte balance, preventing headaches, dizziness, and fatigue that often come with switching to the keto diet. The adult body comprises around 60% water at any given time, and it’s essential to replace fluids lost through everyday processes.
Proper hydration helps support kidney function, which is essential for processing a keto diet’s higher fat intake (and ketone production). Drinking enough water also helps support healthy digestion and prevents constipation.
Avoid Strenuous Exercise
Replace Electrolytes
Switching to a keto diet can lead to more excretion of electrolytes like sodium, potassium, and magnesium. Replenishing these electrolytes can help minimize keto flu symptoms like headaches, tiredness, and muscle cramps. Eat various nutrient-richfoodsand consider using electrolyte supplements to support the transition.
Get Adequate Sleep
Sleep is your body’s time for rest, repair, and rejuvenation. Getting enough sleep supports your body’s natural recovery and adaptation during the transition to ketosis. Quality rest seven to eight hours per night for adults) can help reduce fatigue, irritability, and brain fog commonly associated with keto flu. Once the keto flu is over, evidence suggests that the keto diet can be beneficial for overall sleep.
Prioritize Nutrient-Dense Foods
Nutrition remains a top priority while on the keto diet. Consuming adequate healthy fats and fiber is important while controlling your carbohydrate intake. Fat helps maintain energy levels and satiety (a content feeling of fullness). Foods high in fat include:
Fiber from complex carbs—like whole grains, leafy greens, seeds, broccoli, and Brussels sprouts—supports digestion and prevents constipation.
Try Supplements
Certain supplements, such as electrolyte supplements with potassium, magnesium, and sodium, may help fill nutritional gaps as you switch to a keto diet. A multivitamin may be another good choice to ensure you get enough vitamins and minerals for overall health.
Medications for Acid Reflux
If you experience digestive symptoms like acid reflux during your transition to a keto diet, it may be helpful to use acid reflux or heartburn medications. Still, long-term reliance on these medications may not be ideal, so it’s important to address the root causes of your indigestion with a healthcare provider. While more research is needed, there is some evidence that a very low-carb diet may be helpful for people with acid reflux.
Why Do Some People Get the Keto Flu and Not Others?
Whether you experience the keto flu depends on how your body responds to adopting a keto diet and drastically cutting out carbs.
People who are used to eating a high-carb diet are more likely to experience noticeable side effects from cutting their carbohydrate intake compared to people who don’t have to reduce theircarb intakeas much to align with a keto diet pattern.
Other factors may also be involved, such as genetics and hydration status, plus any existing health conditions that could affect how your body responds to the keto diet.
How Long Do the Symptoms Last?
The keto flu generally lasts from a few days to about a week, but it can affect everyone differently and depends on how your body responds to the switch in your diet. Making sure that you stay hydrated and are getting enough electrolytes, while slowly reducing your carb intake, can help keep symptoms to a minimum.
Who Should Avoid Ketogenic Diets?
Keto diets are not for everyone, and it’s probably best for certain groups to avoid them, such as:
Before making any significant changes to your diet pattern, it’s always a good idea to speak with a healthcare provider, such as a dietitian, to ensure it’s safe and appropriate for you.
When to Contact a Healthcare Provider
If you’re considering switching to a ketogenic diet, consult a healthcare provider if you have existing health conditions like diabetes, heart disease, or problems with the pancreas or liver.If you’re embarking on the diet for weight management and to improve your health, consider speaking with a registered dietitian who can help you create a nutritionally adequate plan tailored to your needs and preferences.
Consult a healthcare provider if you experience significant symptoms like dizziness, confusion, extreme tiredness, or digestive issues after starting the keto diet.
Summary
Switching to a keto diet can look different for everyone, including regarding health goals, macronutrient ratios, carb choices, and side effects. Many people report experiencing the keto flu when they drastically cut their carb intake. This side effect is annoying but temporary.
Consider how you can support your body through this transitional period with light exercise, nutrient-dense foods, adequate rest, and speaking with a healthcare provider when necessary.
9 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
Ghimire P, Dhamoon AS.Ketoacidosis. [Updated 2023 Aug 8]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK534848/
Masood W, Annamaraju P, Khan Suheb MZ, et al.Ketogenic diet. [Updated 2023 Jun 16]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK499830/
Brinkman JE, Dorius B, Sharma S.Physiology, body fluids. [Updated 2023 Jan 27]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK482447/
Batch JT, Lamsal SP, Adkins M, Sultan S, Ramirez MN.Advantages and disadvantages of the ketogenic diet: a review article.Cureus. 2020;12(8):e9639. doi:10.7759/cureus.9639
O’Hearn, L. Amber.The therapeutic properties of ketogenic diets, slow-wave sleep, and circadian synchrony.Current Opinion in Endocrinology & Diabetes and Obesity. 28(5):p 503-508. doi:10.1097/MED.0000000000000660
Dowis K, Banga S.The potential health benefits of the ketogenic diet: a narrative review.Nutrients. 2021;13(5):1654. doi:10.3390/nu13051654
Latorre-Rodríguez, A. R., Munir, S., & Mittal, S. K. (2024).Effect of ketogenic diet on gastroesophageal reflux disease: Literature review and exploratory study. Foregut. https://doi.org/10.1177/26345161241249381
Watanabe M, Tuccinardi D, Ernesti I, et al.Scientific evidence underlying contraindications to the ketogenic diet: an update.Obes Rev.2020;21(10):e13053. doi:10.1111/obr.13053
Meet Our Medical Expert Board
Share Feedback
Was this page helpful?Thanks for your feedback!What is your feedback?OtherHelpfulReport an ErrorSubmit
Was this page helpful?
Thanks for your feedback!
What is your feedback?OtherHelpfulReport an ErrorSubmit
What is your feedback?
