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How to Overcome the Keto Flu

author avatar Dr. Eric Berg 03/27/2024

When starting on the ketogenic diet, many people do not realize that transitioning from a high-carb to a low-carb diet can lead to the emergence of what's called 'keto flu' - an assortment of disagreeable symptoms that make adhering to the new eating routine seem difficult.

Learn about what causes the keto flu and what steps you can take to prevent the symptoms while supporting your overall health.

Understanding Keto Flu

The ketogenic diet, a lifestyle change that involves drastically cutting carbs and burning ketones for energy, often brings with it an unwanted guest: the keto flu.

This is not your typical flu but a collection of symptoms experienced by those transitioning from high-carb foods to low-carb.

Keto flu manifests in various ways, including fatigue, body aches, brain fog, and even headaches - all mimicking regular flu-like symptoms.

However, what sets this apart is intense cravings for sugar and carbohydrates as your body adjusts to its new fuel source.

Symptoms of Keto Flu

Though varying among individuals, keto flu symptoms can include feelings such as dizziness or irritability and physical discomforts like nausea or muscle cramps due to electrolyte depletion.

A common yet challenging symptom during this transition phase includes difficulty focusing - colloquially called "brain fog."

This period also witnesses strong desires to consume sugary or starchy vegetables, which indicates carbohydrate withdrawal since our bodies have previously been so used to deriving energy from these sources before shifting onto fat-burning mode under ketogenic diets.

Why does 'keto flu' occur?

A shift into ketosis, the metabolic state defining ketogenic dieting where fats instead of sugars are burnt for energy, results in the onset of 'keto-flu.'

The sudden decrease in carb intake triggers several changes within our bodies, leading us closer to achieving the weight loss goals associated with this dietary approach.

However, it doesn't come without challenges, most notably the 'carb withdrawal' phase triggering uncomfortable side effects associated with keto flu.

This occurs because when you reduce your intake of carbohydrates, your insulin levels decrease. As a result, your kidneys start excreting excess water and essential minerals like sodium, causing an imbalance that leads to the unpleasant symptoms mentioned earlier.

This can make the initial stages of transitioning to a low-carb diet quite challenging at times. However, there are simple remedies available to help alleviate these symptoms.

Role of Nutrients in Overcoming Keto Flu

The body needs to adjust from utilizing glucose as energy to using ketones, necessitating certain nutrients like B vitamins and electrolytes for this shift.

During this transition, the body requires specific nutrients such as B vitamins and electrolytes to support its new fuel source.

Importance of B Vitamins in Ketosis

B vitamins are essential players during metabolism, assisting with fat and protein conversion into usable energy. This is especially important when your primary fuel switches from carbohydrates to fats on a keto lifestyle.

You can obtain these vital nutrients through various food sources like eggs, fish, meat, and seeds or supplements if necessary.

Electrolytes - The Key Players

In addition to the role played by vitamin Bs during this transitional phase, electrolyte minerals carrying an electric charge are also pivotal. They maintain fluid balance within our bodies and aid muscle contractions.

When you begin following a ketogenic diet, drastically cutting carbs, it could lead to depletion of these minerals, causing keto flu symptoms.

  1. Potassium regulates fluid balance inside cells, supporting heart health and regulating blood pressure.

  2. Magnesium helps nerve functions, manages insulin levels, enhances the immune system, and maintains heartbeat rhythm.

  3. Sodium plays a crucial part in managing water levels and preventing dehydration-related issues.

To avoid experiencing typical keto flu symptoms altogether, replenishing lost minerals either by consuming high-salt foods or taking supplements under the guidance of medical professionals becomes imperative, ensuring optimal hydration and nutrient availability throughout the entire metabolic transition period.

Unfortified Nutritional Yeast - A Key Source of B Vitamins

The journey to a ketogenic lifestyle often includes the dreaded keto flu. However, one can ease this transition by incorporating specific nutrients into their diet. Unfortified nutritional yeast is an excellent source of vital nutrients, particularly B vitamins.

Battling Keto Flu with Unfortified Nutritional Yeast

This deactivated form of Saccharomyces cerevisiae yeast boasts a nutrient-rich profile and contains essential B vitamins like thiamine (B1), riboflavin (B2), niacin (B3), pantothenic acid (B5), pyridoxine (B6), and folate (B9).

These play crucial roles in energy production during ketosis, helping alleviate typical keto flu symptoms.

In addition to being high in B vitamins, it also offers trace minerals, including zinc and selenium, which support overall health while transitioning into ketosis.

Integrating It Into Your Daily Diet

Nutritional yeasts are not just nutritious but versatile, too. Its cheesy flavor makes it a perfect substitute for cheese among vegans, lactose-intolerant individuals, or anyone looking forward to adding an extra punch both nutritionally and tastefully within meals, irrespective of whether they're following ketogenic diets.

  • Sprinkle some over salads,

  • Mix them into soups, stews,

  • Add scrambled eggs enhancing flavors along with all these beneficial nutrients.

Dealing With Fluid Loss During Ketogenic Diet Transition

Fluid loss when starting keto is mainly due to the body's response when shifting from a high-carb diet.

Electrolyte Imbalance Due To Sugar Withdrawal

Stored alongside water and electrolytes like sodium, potassium, and magnesium is glucose your body uses for energy.

As you reduce your carbohydrate intake during the transition into ketosis or a keto lifestyle, this reserve depletes, leading to water loss and an imbalance in these crucial minerals.

This electrolyte imbalance, commonly called 'carb flu,' can cause typical keto flu symptoms such as fatigue or headaches.

The initial weight reduction many people experience at the start of their ketogenic journey is primarily due to this fluid depletion rather than the actual fat-burning process.

Rehydrating Your Body While On A Ketogenic Diet

To counteract the effects of lost fluids & electrolytes while transitioning towards a state of nutritional ketosis, it isn't enough to drink lots; replenishing those vital salts becomes equally essential too.

A more effective approach would be consuming beverages rich in these nutrients, like bone broth, or using high-quality electrolyte powders.

Foods naturally abundant in them, such as avocados (potassium), nuts/seeds (magnesium), and cheese/eggs (calcium) could be included within your dietary plan.

Maintaining a balance between hydration and mineral supplementation while avoiding overconsumption, which may lead to its own set of problems, including bloating and digestive discomforts, becomes essential here.

Treating Keto Flu Symptoms Appropriately

Keto-flu has no specific cure since it isn't an illness but merely indicative of metabolic changes in our bodies as they switch fuel sources from carbohydrates to fats (ketones).

Ketogenic foods

Healthy Eating and Its Impact on Easing Into Ketosis

Careful dietary choices during the transition from high-carb to ketogenic can help reduce or even prevent flu-like symptoms associated with keto flu.

Impact of Dietary Choices on Experiencing Keto Flu

Moving away from starchy vegetables and other high-carb foods doesn't just mean drastically cutting carbs.

It also involves increasing your intake of quality proteins and healthy fats, vital components in supporting ketone production - the primary fuel source for a ketogenic lifestyle.

Foods abundant in omega-3 fatty acids, such as chia seeds, flaxseeds, fish like salmon and mackerel, and walnuts, have been known to exhibit anti-inflammatory properties.

These food items not only help calm keto flu side effects but also aid cognitive function, thereby reducing brain fog - another common symptom experienced when transitioning into ketosis.

In addition, ensuring adequate protein consumption is vital to preserving muscle mass, especially during periods of significant fat loss under a low-carb regime. Good sources include lean meats (like chicken breast) and eggs.

Incorporation of Essential Supplements for an Easy Transition

Besides making informed food choices designed specifically around mitigating typical keto flu symptoms associated with carbohydrate restriction, it is important to incorporate essential supplements into daily routines.

This approach helps provide nutrients that might otherwise become deficient due to a lack of carbohydrates while following Keto Diet guidelines.

An electrolyte supplement high in potassium and magnesium could be highly beneficial in preventing potential electrolyte imbalances.

These imbalances often occur when fluid losses significantly increase during sugar withdrawal, leading to similar discomforts experienced by individuals.

Keto Flu on Intermittent Fasting

Experiencing the keto flu during intermittent fasting is not uncommon. Intermittent fasting is a dietary approach that involves cycling between periods of eating and fasting. During this transition, some individuals may encounter symptoms known as the keto flu.

The keto flu is a collection of flu-like symptoms that can occur when the body adapts to a ketogenic diet, often combined with intermittent fasting.

These symptoms may include fatigue, headaches, irritability, and nausea. While challenging, the keto flu is generally temporary and signifies the body's shift from using carbohydrates to fat as its primary energy source.

Staying well-hydrated, maintaining proper electrolyte balance, and gradually easing into the diet and fasting regimen can help minimize the discomfort associated with the keto flu.


Transitioning to a ketogenic diet can lead to the emergence of keto flu, characterized by symptoms like fatigue, headaches, and cravings.

Understanding the causes of keto flu, such as electrolyte imbalances and carbohydrate withdrawal, is crucial for managing its effects. Incorporating nutrient-rich foods, electrolyte supplements, and hydration strategies can help ease the transition and support overall health during this dietary change.

By making informed dietary choices and gradually adapting to the ketogenic lifestyle, individuals can minimize the discomfort of keto flu and reap the long-term benefits of a low-carb, high-fat diet.

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