If you're interested in trying the keto diet for weight loss, you might have heard about something called the keto flu. Although it's quite a bit different from seasonal flu, which is a contagious respiratory illness caused by influenza viruses, the keto flu is also not too fun. Any keto dieter who's had this pesky problem in the past will immediately recognize it.
What is the keto flu?
The keto flu is a loose collection of general symptoms that some folks experience while on the keto diet, according to Popular Science. Keto flu symptoms can include brain fog, nausea, fatigue, headaches, dehydration, and irritability. However, the keto flu can vary widely from person to person — and it's worth noting that not every single person who tries the keto diet necessarily gets keto flu.
Experts aren't sure exactly what causes keto flu, but it tends to happen as the body first begins to adapt to the change in eating and usually lasts less than a week. Teresa Fung, a professor at Simmons College and a clinical nutritionist, told Popular Science that anytime people have a big shift in the way they eat, the body needs a bit of time to adjust. As you may be aware, the keto diet is a very high-fat, low-carb diet, which is vastly different from the way many people in America eat. "They’re cutting out a large chunk of the usual foods they eat and starting to eat a huge amount of fat," Fung said. "It’s very heavy and the stomach doesn’t necessarily feel good about that."
Even some health professionals who have tried the keto diet got the keto flu. Kristin Kirkpatrick, MS, a registered dietitian and wellness manager for the Cleveland Clinic Wellness Institute, describes her experience as such: "As my body moved from relying on a steady supply of glucose to ketosis, or fat-burning, the 'keto flu' hit. I felt tired, had wild sugar cravings, and was mean to my poor husband. It was a rough start."
How to Get Rid of Keto Flu
Staying hydrated is obviously important all the time, but drinking lots of water during keto flu is especially crucial. Since you've cut so many carbs from your diet, your body is has to call on your glycogen stores, which are where your body stores glucose for the long term. This glycogen soaks up water — explaining why you may need to drink more water than you ever did before going on the diet so that you don't get dehydrated.
Along with getting enough fluids, it may also be a good idea to eat more magnesium, as Dominic D'Agostino, PhD, told PureWow in an interview. "Blood work in people experiencing keto flu often shows a dip in magnesium," he said. Pumpkin seeds, almonds, avocados, and dark leafy greens such as spinach and kale are some examples of keto-friendly foods that also boast a lot of magnesium. Dr. D'Agostino also suggests adding more fats to your diet, in order to help you start burning fat instead of glucose at a quicker pace. If you're struggling to find more fats to eat than you're already consuming, try drinking your fats; a keto coffee recipe — such as one with hot coffee, coconut oil, and butter — may be an easier addition to your daily routine.
If you want to try to prevent keto flu in the first place, your best bet is to ease into the diet and not go completely cold-turkey on carbs overnight. It may also be helpful to start slowly adding more healthy fats such as olive oil into your daily calorie intake before you start. Although there's no surefire method to keep keto flu away, you can feel better knowing that a slow start will be much less shocking to your body.
Remember, always get the OK from your doctor before changing your diet — especially if it's a big shift like keto. If any diet out there makes you constantly feel awful physically and mentally for a long period of time, it's probably not the right diet for you.