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Keto Flu: Causes, Symptoms and Remedies

If you are new to the ketogenic diet, you might experience headache, brain fog or might find it hard to concentrate.

Most people experience these symptoms during the first week, and might find it really annoying.

Don’t fret: it’s natural to experience keto flu during ketosis or when on carb withdrawal.

Yes, keto flu is real and it afflicts many people who just start out on a keto-friendly diet.

As the keto diet is different than any other forms of diet, it makes sense that you will start to experience certain symptoms as it begins to detox.

Sometimes the symptoms can be so uncomfortable that it can be tempting to throw in the towel, especially when you’re just starting out and haven’t really seen significant results yet.

You can get over it too, don’t worry!

What is Keto Flu?

Also referred to as the “carb flu,” the keto flu is the body’s natural reaction when carbohydrates are abruptly and significantly reduced or eliminated from the diet.

It’s almost like feelings of withdrawal that you experience when you suddenly aren’t feeding your body all those carbs you’ve been used to eating.

Basically, it’s a reaction of the body when it switches from burning sugar as a fuel source to burning body fat for energy instead.

Sugar is an addictive substance, so it makes sense that people would experience withdrawal symptoms when they are suddenly cut off from sugar consumption.

In fact, studies have shown that sugar can be just as addictive as drugs. I know first hand that sugar addiction is real and causes withdrawal symptoms when it’s abruptly eliminated from the diet.

I was a self-proclaimed sugar addict and constantly reached for baked goods that were loaded with refined sugars.  I binged on donuts, muffins, cake, chocolate bars . . . you name it.

Sometimes I found myself eating sugary foods without even realizing that I was hooked.

Then, when I finally made the decision to lead a healthier lifestyle and adopt the ketogenic way of eating, I learned the hard way that sugar withdrawal was real. My energy level dropped and I was worried.

I experienced all the nasty symptoms that one would go through when their body is no longer burning sugar for energy. It sucked, but it was a temporary phase that I quickly overcame.

What Causes Keto Flu?

When you just start out eating healthy, aren’t you supposed to start feeling great?

Yes, you absolutely should, but not necessarily right away. Your body needs to go through the process of detoxing, which can make you feel miserable in the meantime.

The keto flu is caused by the body’s transition to burning fat for fuel rather than sugar. Our bodies burn glucose (or carbs) by default as its main source of energy.

But as soon as we make the switch to a low-carb diet where carbs are drastically reduced, our bodies start to burn fat for energy instead. It’s during this transition phase that the keto flu sets in, albeit temporarily.

Fat is the body’s backup energy source that’s only used when sugar levels in the diet are sufficient. When the body starts burning fat for energy instead of sugar, ketosis sets in.

The majority of the symptoms are due to a lack of salt and water caused by a temporary boost in urine production as the body starts to get into ketosis.

It’s the state of ketosis that we strive to achieve when on the ketogenic diet, as this is the mode in which fat-burning really starts to go into overdrive.

What Are the Symptoms of Keto Flu?

Making the switch from a carb-loaded diet to a ketogenic diet that’s essentially void of carbs and sugar is a huge deal.

That’s a major thing for the body to have to go through, and as such, the body needs some time to get accustomed to this new diet.

For some people who eat a diet predominantly made up of carbs, this transition phase is usually pretty tough.

In fact, the symptoms can be worse for those who eat mostly carbs compared to those who aren’t as dependent on sugary foods. For me, I was in the former category, so my symptoms were pretty uncomfortable.

Symptoms of keto flu can range from mild to severe.

Some people might experience only some of the symptoms, while others might experience the whole spectrum of symptoms. The following are typical symptoms of keto flu:

  • Sugar cravings
  • Constipation
  • Diarrhea
  • Nausea
  • Vomiting
  • Stomach pain
  • Irritability
  • Weakness
  • Headaches
  • Dizziness
  • Lack of concentration
  • Muscle cramping
  • Difficulty sleeping

Keto flu doesn’t go on forever and usually lasts about a week, with peak symptoms occurring anywhere between days 3 and 5 of the diet. It might disturb your sleep quality because of the increase in ketone levels, but it’s totally natural when on a low-carb diet.

The good news is it’s not really a side effect and that you’ll start feeling great very soon. Better still, there are things you can do to help you alleviate these symptoms rather quickly.

How to Get Rid of Keto Flu?

The changes that the body undergoes when quitting carbs “cold turkey” are pretty significant, which is why symptoms of the keto flu set in.

But there are a few things I did to help me manage my symptoms that might work for you too:

1. Drink Lots of Water

As mentioned earlier, one of the biggest reasons for the keto flu is a shortage of water, so an obvious way to help counter the symptoms is to stay hydrated and drink enough water.

Being in ketosis can quickly deplete water stores in the body that can cause dehydration.

That’s because glycogen sticks to water in the body, and when you reduce your carb intake, glycogen levels drop, causing water loss.

Drinking plenty of water will help provide you with the energy that is often zapped and prevent any headaches from ensuing.

Always have a bottle of water with you at all times so you can continuously sip on it throughout the day and have it handy.

2. Replenish Your Electrolytes

Making yourself a simple electrolyte drink can be a great way to alleviate your keto flu symptoms.

When you’re in ketosis, insulin levels drop, causing the kidneys to release a ton of sodium from the body.

All that lost sodium needs to be replenished, and drinking an electrolyte beverage can be a great way to do that.

Don’t bother with store-bought electrolyte beverages, as many of these are typically loaded with simple sugars. Instead, make your own with water, sea salt, and lemon juice.

You might also want to drink bone broth to keep your electrolyte levels up.

Bone broth is a simple and tasty way to add more water and electrolytes to your diet. You can also season your food with more salt to help make sure you’re giving your body an optimal balance of electrolytes to reduce keto flu-like symptoms.

3. Eat Plenty of Healthy Fats

The ketogenic diet requires that between 65% to 80% of your daily calories come from healthy fats.

Dietary fat consumption not only provides your body with an alternative fuel source, it also helps to keep you satiated and prevents sugar cravings, which is a common symptom of the keto flu.

Make sure you are eating high-fat to help keep sugar cravings at bay.

Snack on an extra handful of macadamia nuts, add another tablespoon of coconut oil to your coffee, or add a pat of butter when cooking your favorite dish to add some more fat to your diet.

Adding supplements like MCT oil can also help!

4. Maintain Your Carbs

You might have to add some high-carb food to your diet at certain point when on keto diet.

Yes, I just said it. While getting into ketosis requires that you drastically reduce your carb intake, there are certain cases when you might need to increase your carb consumption when on the keto diet.

If you are very active or if your body has a high metabolic flexibility, your might have to add more carb to alleviate your symptoms during the transition phase.

In this case, it might be OK to add a small serving of sweet potatoes to your meal, for instance, to help manage your symptoms. Don’t worry: it’s not going to affect your weight loss.

You might also feel major symptoms of keto flu if you were previously heavy on carbs before starting this diet.

In this case, it might be necessary to gradually eliminate carbs if the symptoms are particularly uncomfortable and unbearable.

While this will help slow the process down, it can definitely relieve any symptoms of the keto flu.

Make sure to check the keto food pyramid and avoid processed food when preparing a keto meal plan.

5. Don’t Exercise Too Hard

Exercise is always a recommended part of any healthy diet if you’ve been given the clear from your doctor.

But sometimes overly strenuous exercise can actually exacerbate flu-like symptoms.

Typical keto flu symptoms include muscle cramps, muscle soreness, weakness, and stomach pain which can be made worse with hard exercise.

On the first few days of being on a ketogenic diet, consider engaging in gentle exercise instead.

6. Get Enough Sleep

Irritability and fatigue are common symptoms of the keto flu, which can be made worse if you’re not getting enough restful sleep.

Shortage of quality sleep is associated with elevated levels of cortisol, the “stress hormone,” which can make your feelings of irritability even worse.

Getting enough quality sleep might be easier said than done, but there are some things you can do to induce a good night’s rest, including:

  • Cutting back on caffeine
  • Developing a regular nighttime routine
  • Shutting off all lights and electronics
  • Taking a soothing bath
  • Waking up early every morning

Final Thoughts

There’s no doubt that the ketogenic diet can have amazing results.

For me, I was able to experience a significant change in my body composition and lose weight faster than I ever had on any other diet I’ve ever tried.

But before I was able to see results, I had to go through a bit of a valley first, known as the dreaded “keto flu.”

I admit, it wasn’t enjoyable, but it was only temporary.

I was even able to alleviate some of my symptoms by adopting the above-mentioned tactics, which I highly recommend you do too in order to get over the hump.

Once you make it through to the other side, you’ll be glad you stuck with it.

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