Ketosis kinda sounds like the medical term for bad breath, but it’s actually what the “keto” in keto diet stands for. And, if you follow the keto diet or are interested in it, getting your body into ketosis is what you’re going for.
In case you’re not familiar with keto, it’s a diet that is very high in fat and low in carbs. The goal is to get yourself into a state called ketosis, which requires eating less than 30 to 40 grams of carbs a day, explains Alissa Rumsey, R.D., C.S.C.S.
“When you only eat a very limited amount of carbs, your body breaks down fatty acids from your fat stores and forms ketones, which are released into the bloodstream by the liver,” Rumsey says. “Ketosis occurs when blood ketones are higher than normal.”
When this happens, your body also starts using fat for fuel—hence, the results that celebrities like Kourtney Kardashian and Vanessa Hudgens have raved about it.
Only one problem: How do you actually know if you’re in ketosis? Experts say there are six big signs and symptoms you should look for—besides the weight loss you’ll probably be super-tuned-into.
1. You Have Bad Breath
Speaking of halitosis… It’s unfortunate, but true: One of the major signs of ketosis is stinky breath. When you’re in this state, your body breaks down fat and proteins for energy, creating byproducts that have to be eliminated, says Scott Keatley, R.D., of Keatley Medical Nutrition Therapy. There are a few ways it does this, he says: through your poop, pee, sweat…and breath.
A byproduct of this breakdown of fat and protein into energy is a ketone body called acetone (the same stuff that’s in nail polish remover). “A little bit of acetone on the breath has a fruity smell, but a lot has a very distinct astringent smell that is quite unpleasant,” Keatley says. “This is a general sign that you’re in ketosis and you’re burning protein or fat as a source of energy.”
2. You Feel Totally Wiped Out
When you first go into ketosis, your body gets confused by the fact that it doesn’t have the normal amount of carbs to burn for energy, says Peter LePort, M.D., a bariatric surgeon and medical director of MemorialCare Surgical Weight Loss Center at Orange Coast Medical Center in Fountain Valley, Calif. As a result, you feel completely exhausted.
3. …But Then You Super-Energized
Eventually, your body figures out that you can get by just fine by burning fat and protein for energy, and so you start to feel a little more energetic, LePort says. But that’s likely a placebo effect more than anything, given that it’s basically just an improvement from feeling super tired all the time, he says.
4. Your Appetite Decreases
This is a legit phenomenon that happens, but it’s not totally clear why. There are some theories, though, Keatley says. It could be that the bacteria in your gut changes due to your new diet, he says. It could also be that the ketones affect the hypothalamus in your brain and cause a different release of hormones, making you less hungry in the process, LePort says. Whatever it is, it’s not uncommon to feel less hungry when you enter ketosis.
5. You Spend Tons Of Time In The Restroom
When you go on keto, your start eating some serious fat, and your body just isn’t ready for it, Keatley says. “Your body doesn’t digest it properly and the bacteria in your gut is not ready to break it down,” he explains. This can lead to diarrhea or a temporary disorder called steatorrhea, which causes really smelly poop. “This should subside after a little bit but you can always ease into a keto diet rather than jump all in to avoid these issues,” Keatley says.