How Long Does the Keto Flu Last?

If you recently started your keto journey, you may feel unwell, similar to having the flu. Experiencing these flu-like symptoms (the “keto flu”) is nothing to be concerned about—it can actually be a sign your body is adapting to ketosis.

Transitioning your body to burn fat instead of carbs for energy requires significant changes in your metabolic state. As your body adapts, the keto flu will go away on its own.

Let’s talk about how long the keto flu lasts and how you can reduce the symptoms fast.

How long does keto flu last?

If you just started keto and suffer symptoms of keto flu, you may be wondering how long they will last. The good news is that as your body adjusts, symptoms typically disappear within the first week or two.

Keto flu is temporary. Some people experience only mild symptoms, and others have a strong case of the keto flu. Understanding what causes keto flu and how to tweak your ketogenic diet helps to improve symptoms and lets you enjoy the health benefits of keto faster.

What is keto?

Keto is a high-fat, moderate-protein, and low-carb diet that switches your metabolism from burning sugar to burning fat.

As you break down fat, your liver creates ketones, a type of acid. Ketones enter your circulation to fuel your body—this state is known as ketosis.

Your body only makes ketones when sugar is in short supply, so you have to limit your daily carbs to 20 to 50 grams.

Keto is incredible for your health. You have more energy and improved cognitive function as a result of the increase in your metabolic rate. In fact, research shows that keto is one of the most effective ways to lose weight fast.¹

Keto flu symptoms

Your risk of keto flu symptoms depends on your metabolic flexibility. Your age, genetics, current body weight, and lifestyle habits influence how quickly your metabolism can shift into fat-burning mode.

Keto flu symptoms can vary, but the most common symptoms are:

• Body aches
• Muscle weakness
• Brain fog
• Fatigue
• Headaches
• Muscle cramping
• Insomnia
• Irritability
• Muscle soreness
• Nausea
• Sugar cravings

What causes the keto flu?

Symptoms of the keto flu can feel similar to an infection, but there is no need to be concerned. Experiencing keto flu is a result of the powerful changes in your metabolism in response to lowering your carb intake while increasing your fat intake.

Here are some reasons why you may experience symptoms of the keto flu.

Dehydration and electrolyte loss 

As your body transitions to keto’s high-fat, low-carb protocol, your insulin levels drop. Insulin is a crucial metabolic hormone responsible for blood sugar regulation and fat storage.

Low insulin triggers ketosis but also causes water loss and electrolyte depletion in the early days of keto-adaptation. This rapid water loss is commonly observed as quick weight loss but also leads to muscle cramps, headaches, and fatigue.

Increased B vitamin requirements 

Using fat as a fuel source requires different metabolic pathways than burning sugar. Efficient ketosis relies on good levels of B vitamins.

Switching to keto can cause a dip in your B vitamin levels, resulting in typical keto flu symptoms like body aches, low energy, and sugar cravings.

Metabolic changes 

It’s important to understand that adapting to ketosis takes time. Your body likely has been burning sugar as fuel for years or even decades, and your cells and organs must slowly adapt to fat as the primary fuel. Brain fog and body aches are hallmarks of this transition.

Carbohydrate withdrawal  

Starting keto can cause carb withdrawal and may make your keto flu symptoms worse. When burning sugar for energy, your brain is primed to seek out more carbs whenever blood sugar is low.

The transition to a low-carb diet can cause intense sugar cravings, irritability, and lightheadedness.

How to get rid of the keto flu fast

Don’t feel discouraged if you are suffering from keto flu. As your body adapts to the keto diet, this miserable feeling will diminish, and there are plenty of steps you can take in the meantime to reduce symptoms.

Stay hydrated and replenish electrolytes 

As your body adapts to keto, you lose water and essential electrolytes like potassium, sodium, calcium, and magnesium. Replacing electrolytes is vital to fight keto flu symptoms.

Bone broth is keto-approved and naturally high in electrolytes. Bone broth benefits also stimulate bile production, supporting fat digestion and absorption.

Alternatively, find a good quality electrolyte product. Choose a keto-friendly option without added sugars or dextrose.

Because dehydration can worsen keto flu symptoms, you should drink plenty of water. Increased water loss in the early stages of keto-adaptation means you have to compensate and increase your water intake.

Eat more fat and calories 

Transitioning to keto generally requires significant changes in your diet. You suddenly have a very low carbohydrate intake which can cause intense carb cravings. Ensure that you eat enough fat and calories to curb cravings and hunger.

Listen to your body and adjust your meal plan if needed. Some people find it easy to become fat-adapted, and others may need a slower transition, gradually increasing quantities of healthy fat.

Eat nutrient-dense, high-quality foods 

A healthy and balanced ketogenic diet doesn’t just require low-carb and high-fat foods. The best foods for the keto flu are nutrient-dense foods that support healthy vitamin and mineral levels.

B vitamins are essential for fat-burning—so not including enough vitamin B-rich foods in your diet can worsen your keto flu symptoms and slow keto-adaptation.

It’s important to do a Healthy Keto® diet instead of dirty keto. Healthy Keto replenishes vitamins and minerals by including plenty of green leafy vegetables, avocado, nuts and seeds, pork, seafood, and full-fat dairy.

Get plenty of sleep

It’s not uncommon to experience sleep issues during the early stages of keto. This isn’t anything to be concerned about, and your sleep quality will improve as your body adjusts to keto.

Good sleep hygiene and a bedtime routine can help you overcome sleep-related symptoms when transitioning into ketosis.

Adjust your exercise routine

It takes your body a while to become efficient at burning fat. Until you are fully keto-adapted, you want to avoid high-intensity exercise to minimize fatigue and muscle pains.

Walking, swimming, and weight lifting are good choices during the early phases of your keto diet.

Key takeaways

Going keto means your metabolism undergoes significant changes, and you may suffer some keto flu symptoms along the way. The good news is that these temporary symptoms will disappear once your body adjusts to this low-carbohydrate diet.

Pay attention to your body and tweak your keto plan if necessary. Include electrolytes, stay hydrated and eat plenty of nutritious keto-friendly foods. Allow your body to rest and modify your exercise routine until your body is fat adapted.

FAQ

Sources

1. “The Ketogenic Diet: Clinical Applications, Evidence-based Indications, and Implementation – StatPearls.” StatPearls [Internet]. StatPearls Publishing. https://www.ncbi.nlm.nih.gov/books/NBK499830/ ↩︎
2. Bostock ECS, Kirkby KC, Taylor BV, Hawrelak JA. Consumer Reports of “Keto Flu” Associated With the Ketogenic Diet. Front Nutr. 2020;7:20. doi:10.3389/fnut.2020.00020 https://pmc.ncbi.nlm.nih.gov/articles/PMC7082414/ ↩︎