What Is Keto Flu? Symptoms, Remedies & How to Avoid

Last Update: September 27, 2022

Embracing a new way of eating is supposed to make you feel good, right? Typically, yes. But if you’ve ever experienced “keto flu” symptoms—or heard about them from others who have gone before—you might be wondering about what to expect when transitioning to a ketogenic diet. Today, we’re covering keto flu symptoms and remedies, with tips from keto experts to get you through the worst of them.

What Is the Keto Flu?

The first thing to know is the keto flu is not the same as the contagious respiratory illness caused by influenza. Rather, the keto flu is named for the occasionally uncomfortable symptoms associated with transitioning to a keto diet when your body begins to start using fat—rather than carbs—as its primary source of energy. Symptoms typically appear between two and seven days after starting a ketogenic diet.

What Are the Symptoms of Keto Flu?

Wondering what causes the keto flu? So is everyone else. Harvard Medical School notes that we don’t really know why some people have a tougher time with this diet swap—and no one can specify if it’s due to detoxing, carb withdrawal, a change in the gut microbiome, or an immunologic reaction. If you do start feeling out of sorts, here are some of the most commonly cited symptoms of keto flu, in no particular order:

  • Keto flu headache
  • Keto flu sore throat
  • Keto flu diarrhea
  • Keto flu vomiting
  • Keto flu joint pain
  • Keto flu nausea
  • Keto flu runny nose
  • Keto flu low blood sugar
  • Keto flu muscle cramps
  • Keto flu migraine

How long does keto flu last?

If you’ve recently started following a keto diet and are experiencing any of the symptoms above, they’ll typically subside in a couple of days.

How to Prevent Keto Flu

While there’s no guarantee that you won’t experience some transitional symptoms when starting to eat keto for the first time, Primal Kitchen founder Mark Sisson suggests following the plan outlined in his book, The Keto Reset Diet. He was motivated to share his wisdom after noticing that people often got great results on a ketogenic diet, but they went to extremes to get there, like “suffering through the keto flu, not feeling that great for a long period of time, and hoping that they would emerge on the other side with the results they were seeking.” Sisson knew there could be an easier way to reap the benefits of ketosis, which became the focus of his modified diet.

What Is the Keto Reset Diet?

This plan follows a ketogenic way of eating with an emphasis on resetting your metabolism. Sisson clarifies that the goal isn’t to be in ketosis forever, but to reset your metabolism. “Greater metabolic flexibility means the body can extract energy from whatever substrate is available, whether it’s the fat on your plate of food, the fat stored in your body, the carbohydrate on your plate of food, the glucose in your bloodstream, the glycogen in your muscles, or the ketones that your liver produces.” Maybe even the amino acids, in times of scarcity.” To learn more, check out this video!

Keto Flu Remedies

Need a quick keto flu Rx? First and foremost, hydrate! Drink lots of water, increase your electrolyte intake, and sip bone broth (check out our list of recommended products below.) If symptoms persist or become severe, seek medical attention immediately.

How to Get Over Keto Flu

If you’re experiencing symptoms, here are some ideas for how to minimize keto flu with nourishing liquids.

Ultima Replenisher Electrolyte Powder, Raspberry

This stevia-sweetened powder includes all six electrolytes, plus minerals that work together to help you hydrate.

“One scoop goes a long way. I love using this after hot yoga or when my body is beginning to go into ketosis!”
—Katie, Ky.

Kiss My Keto Exogenous Ketones with Electrolytes – Lemon Lime

You’ll love the citrus flavor in this keto-friendly supplement that delivers electrolytes, BHB salts, and calcium.

“This is a great product for keeping up your electrolytes while doing keto! I’ll definitely continue to buy it.”
—Ramona, Tex.

Thrive Market Organic Chicken Bone Broth

Made with the bones of free-range chickens, this organic broth is slow-simmered with herbs, spices, and veggies.

“This is our go-to broth—it’s a great price and super healthy. I love that there aren’t any additives like sugar.”
—Marissa, Ohio

Kettle & Fire Grass-Fed Bone Broth

Long-simmered with grass-fed beef bones, this broth will quickly become your favorite sippable beverage.

“This is one of the best beef bone broths I’ve tasted. I add it as a base to soup or sip as-is after heating it.”
—Bejay, Calif.

For more, check out our ultimate guide to the keto diet!

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Nicole Gulotta

Nicole Gulotta is a writer, author, and tea enthusiast.

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