We all know what the flu is and have probably dealt with it on multiple occasions. It attacks the lungs, nose, and throat and leads to symptoms such as fever, chills, cough, congestion, runny nose, headaches, and fatigue. But have you ever heard of the keto flu? It is well-known for the number of symptoms that occur when the body is in the process of adapting to a ketogenic diet. But to understand the condition better and in more detail, we spoke to Dr S A Rehman, General Medicine, Noida International Institute of Medical Sciences (NIIMS) College and Hospital, NIU, who also sheds light on its symptoms and treatment options.
Also Read: Here’s How A Ketogenic Diet Can Help Boost Your Metabolism
What Is Keto Flu?
Contrary to popular understanding, keto flu is a real phenomenon experienced by some individuals when they start a ketogenic (keto) diet, says Dr Rehman.
According to him, it refers to a collection of symptoms that can occur as the body adjusts to a very low-carbohydrate, high-fat diet, a characteristic of a keto-friendly diet.
"Common symptoms include headaches, fatigue, dizziness, nausea, irritability, difficulty sleeping, muscle cramps, and sugar cravings," he adds, explaining that these symptoms typically last from a few days to about a week, though some people might experience them for up to two weeks.
Furthermore, the doctor highlights that the duration and severity of symptoms can vary based on individual factors like prior diet, overall health, and how drastically carb intake is reduced.
What Causes Keto Flu?
In a ketogenic diet, the main focus is on consuming a lot of fat, a moderate amount of protein, and very few carbohydrates.
Specifically, carbs should make up only 5–10% of your daily calories, according to StatPearls Publishing. This means if you're eating 2000 calories a day, you should aim for just 20–50 grams of carbs each day.
When you drastically reduce your carbohydrate intake, your body undergoes a major shift in its energy source. Normally, the body relies on glucose from carbs for energy, but with limited carb consumption, it starts breaking down fats into ketones, which are used as an alternative fuel. This process, called ketosis, changes the body's metabolism and can lead to various physical changes as it adapts to the new energy source.
This is when people start to experience a set of symptoms, also called the keto flu.
Dr Rehman says, "This metabolic transition, accompanied by a decrease in insulin levels, can disrupt the body's electrolyte balance, leading to symptoms such as dehydration, electrolyte imbalances, and flu-like symptoms. The body may experience changes in hormone levels and shifts in fluid balance during this adjustment period, contributing to the onset of keto flu."
Also Read: Keto Diet: Benefits And Risks
Does Keto Flu Require A treatment?
According to the doctor, in most cases, keto flu symptoms resolve on their own as the body adapts to the ketogenic diet.
He says, “With proper hydration, electrolyte replenishment, rest, and dietary adjustments, many people find relief from symptoms within a few days to a week. However, in rare cases where symptoms persist or worsen, or if there are underlying health concerns, medical intervention may be necessary.”
He further advises replenishing electrolytes with foods rich in sodium, potassium, and magnesium, like bone broth, avocados, leafy greens, nuts, seeds, and electrolyte supplements.
If you’re on a keto diet, it is also crucial to ensure that you consume healthy fats from sources such as avocados, olive oil, coconut oil, and fatty fish to sustain energy levels and facilitate ketosis.
Moreover, consulting with a healthcare professional can help assess individual circumstances and provide appropriate guidance or treatment if needed, Dr Rehmar says, adding that individuals with pre-existing medical conditions or those taking medications should seek medical advice before starting any new diet.
If you’re planning to follow a ketogenic diet, start gradually rather than making an abrupt change. Get enough rest and avoid strenuous activity during the transition period, as it can help minimise discomfort.