Understanding the Keto Flu

by Brittany, RN, BSNin Health and Wellnesson Posted on

Overcoming the Keto Flu: A Comprehensive Guide to Symptoms, Causes, and Remedies

So you have emphatically started the ketogenic diet and are looking forward to its bounty of benefits. Only to find yourself feeling poorly after the first few days. You’re fatigued, have a headache, you’re easily annoyed, and have a difficult time concentrating.

Congratulations! You have what’s commonly referred to as the keto flu. It is not actually the flu, nor is it contagious or dangerous. It is just unpleasant to endure.

Most people do encounter one or more of these symptoms during the first one to two weeks of starting the ketogenic diet, especially on days 3-5.

Fortunately, it’s only a temporary hurdle, and you’ll soon feel better again. In fact, you may have even more energy than before you started the diet once fully in the wonderful world of ketosis.

Even better, there’s a simple fix that often relieves most or all of these symptoms within 15 minutes. Keep reading to learn more about this helpful tip and other remedies to combat the keto flu and fully embrace the power of ketosis.

Symptoms of the Keto Flu

  • Fatigue and lethargy
  • Headache
  • Irritability
  • Brain fog
  • Dizziness
  • Intense sugar cravings
  • Nausea
  • Muscle cramps
  • Insomnia

Let’s look at the cause

The keto flu occurs as your body transitions from burning sugar to burning fat for most of its energy needs.

Switching from a high-carb diet to a very low-carb one lowers insulin levels in your body. This is one of the primary goals of a ketogenic diet.

When insulin levels are very low, your liver begins converting fat into ketones, which most of your cells will use in place of glucose. When your body begins using fat and ketones for energy rather than glucose, you are in what’s called a state of ketosis.

However, it takes your brain and other organs time to adapt to using this new kind of fuel. Your body will respond to the drop in insulin levels by excreting more sodium in your urine along with water. With this in mind, you may find yourself urinating much more often when first beginning the diet.

Another important component of the keto flu cause is a molecule called glycogen. Your body typically stores extra sugar in glycogen which is generally kept in your cells, along with a lot of water. When you go into ketosis, your body dumps the water that was stored with the glycogen, potentially leading to dehydration.

This rapid fluid depletion and excretion are usually very welcome, as you will see a dramatic weight loss in the early stages of the keto diet. However, the excess loss of sodium and water is what’s also responsible for the many unpleasant symptoms of the keto flu.

The keto transition period is very individualized, and some people may only experience mild fatigue for a day or two after cutting their carb intake. Others however may develop symptoms that strongly impact their ability to function for the first two weeks.

The keto flu doesn’t have to be unbearable for anyone however if the proper steps are taken to remedy it.

The cure for the keto flu

Top tip: Increase your salt and water intake

Since the loss of salt and water is responsible for most keto flu issues, increasing your intake of both can help reduce your symptoms significantly and often eliminate them altogether.

During the first few weeks of your keto lifestyle, whenever you develop a headache, lethargy, nausea, dizziness, or other symptoms, drink a glass of water with half a teaspoon of sea salt stirred into it. This simple trick can often alleviate your symptoms within 15 to 30 minutes.

Some tasty alternatives you can try include sipping chicken or beef bouillon or bone broth. You can stir in a spoonful of salted butter as well if you fancy. Just be sure not to use the low-sodium variety of broths at this time.

Increase your fats

Due to decades of misinformation about all fats being unhealthy, fatphobia has become common amongst those new to the low-carb lifestyle.

A well-balanced keto diet includes enough healthy fats to keep you full and satiated between meals, the ability to go several hours without eating, and the proper fuel for ample energy and focus.

If you sharply restrict your carbohydrates without upping your fat intake, your body will think it is in a starvation-like scenario. This will cause the body to feel hungry, lethargic, and miserable.

Be sure to increase your intake of fat at the beginning of your keto journey until your body can fully become fat-adapted, using ketones for most of its energy. Once you are fat-adapted you can allow your hunger cues to guide you. Simply rein in or consume more fats until you feel satisfied and satiated.

Do a slower transition

Many of the keto flu symptoms are the result of a sudden dietary shift. If you find that the keto flu makes it too difficult to stick with keto, and you have already tried the above two tips, you can try easing into the diet instead. You can accomplish this by following a moderate low-carb version, which provides 20 to 50 grams of carbohydrates per day, versus less than 20 grams per day following the typical keto protocol.

It is important to note that eating slightly more carbohydrates may slow your weight loss and result in less dramatic of health improvements.

But don’t fret, once your body has adjusted, you can begin the process of lowering your carb intake little by little. Reducing your carb intake over the course of a few days or weeks can help your body to adjust more gently and naturally without the negative symptoms.  

Take it easy with physical activity

Walking, stretching, or doing yoga is fine during the transition phase, and may even help you feel better. But when your body is already under stress from trying to adapt to a new fuel system, don’t place an additional burden on it by attempting any type of strenuous workout. Take it easy for the first few weeks and then slowly increase your exercise intensity.

Studies suggest that athletic performance typically recovers — and often improves — within 4 to 6 weeks.

Final take away

In conclusion, the keto flu is a common phenomenon experienced by many individuals transitioning to a ketogenic diet. It is caused by the body’s adjustment to the sudden shift in energy source from carbohydrates to fats. The symptoms of the keto flu include fatigue, headache, nausea, muscle cramps, and sugar cravings among others. However, these symptoms can be mitigated by proper hydration, increasing salt intake, resting, and gradually reducing carbohydrate intake. By implementing these remedies, you can minimize the impact of the keto flu and experience the full benefits of a ketogenic diet. Remember to always consult a healthcare professional before starting a new diet and to monitor your health regularly.