Thinking about giving the keto diet a try? Research suggests that the low-carb diet might help you lose some weight. But you might have to weather some not-so-fun side effects, like the keto flu, especially at first.
What is the keto flu?
The keto flu is a cluster of symptoms that feel similar to the real flu, minus the fever—headache, nausea, fatigue—as your body adjusts to burning fat for fuel instead of carbs. And even once you clear that hurdle, keeping your carbs superlow can potentially cause other problems like constipation or bad breath. So what can you do to feel better? Here’s a look at 6 of the most common keto flu symptoms and other keto diet side effects—and how to manage them.
If you’re feeling nauseous or bloated…
When you’re not used to eating a diet high in fat, drastically upping your intake could leave you a little queasy. That might be especially true if you’re going heavy on butter or coconut oil—they contain medium chain fatty acids that are absorbed differently than the fatty acids found in other fat sources. “Having too much at once can lead to bloating, GI upset and diarrhea,” says JulieStefanski, RD, spokesperson for the Academy of Nutrition & Dietetics. Your GI tract will likely adjust to the higher fat intake over time. But if you don’t want to power through the pain, try reducing your carbs and increasing your fat intake gradually, recommends Will Cole, DC, IFMCP, functional medicine expert and author of Ketotarian. And if large quantities of butter or coconut oil seem to hurt your belly, try cutting back in favor of other fats like olive oil or avocado.
If your head is throbbing…
Carbohydrate withdrawal might initially give you a nasty headache. The pounding of this keto flu side effect should ease up within a week or so, but in the meantime, drinking plenty of water can help. Your liquid needs go way up when you’re eating keto—and dehydration can both cause headaches and make existing headaches worse, say Harvard Health experts. “In order for the body to remove ketones, urine production is amped up slightly. When you’re in a ketogenic state, your body also doesn’t store as much water in the muscles or liver,” Stefanski says. How much should you sip? Everyone’s water needs are different, but in general, you should aim to drink enough so your urine is clear or very pale yellow, says Stefanski.
If your energy is at zero…
Dehydration and adjusting to burning fat for fuel can both contribute to fatigue for keto dieters. “Carbohydrates in our muscles and liver are typically the sources for quick bursts of energy,” Stefanski says. You’ll likely get your energy back within a few days, but in the meantime, make it a point to eat plenty of potassium-rich foods like leafy greens, avocado, peanut butter or salmon. Keto dieters can struggle to get enough of the mineral, since it’s mostly found in higher-carb foods like bananas, beans and potatoes. But getting enough can combat feelings of weakness and fatigue, according to the National Institutes of Health.
If you’re super irritable…
You know that hangry feeling where everything is annoying? The one that sometimes hits when you start craving something sugary around three o’clock? Cutting out the carbs altogether can magnify that by 10, at least for a few days until your body adjusts. In the meantime, do what you can to let your body rest. Take a walk or try some restorative yoga poses instead of pushing yourself through a hard workout. And consider keeping your coffee intake to just a cup or two so it doesn’t potentially disrupt your sleep, the National Sleep Foundation recommends.
If you haven’t had a BM in days…
Low-carb diets tend to fall short on key sources of fiber like whole grains, beans, fruits, and starchy vegetables. And when you don’t get the recommended 25 to 30 grams of fiber daily, you might be more prone to constipation. The fix? Make it a point to eat plenty of keto-friendly, fiber-rich foods daily. “I recommend Brussels sprouts, broccoli, artichokes, and avocado,” Cole says. Drink plenty of fluids too—water makes your stools softer and easier to pass.
If your breath reeks…
Once you reach ketosis, you might start to notice that your breath smells a lot like… nail polish remover. That’s the scent of acetone, a ketone that’s emitted through your mouth as well as your urine when the body is burning fat for fuel. Like most other keto side effects, it should wear off within a week or so. But in the meantime, fill up on bland veggies like cucumbers or raw zucchini. All that chewing stimulates the production of saliva, which can help rinse away foul odors, says the American Dental Association. Find out which diet is better for weight loss: keto or Whole30.
Sources
Julie Stefanski, RD, spokesperson for the Academy of Nutrition & DieteticsWill Cole, DC, IFMCP, functional medicine expert and author of KetotarianHarvard Nutrition Source:“Diet Review: Ketogenic Diet for Weight Loss"Harvard Health: “Quick-start guide to headaches"National Institutes of Health: “Low blood potassium"National Sleep Foundation: “The Link Between Nutrition and Sleep"American Journal of Clinical Nutrition: “Breath acetone is a reliable indicator of ketosis in adults consuming ketogenic meals"American Dental Association: ‘Good Foods for Dental Health’
