What Is Ketosis And How To Tell When You've Reached It

Unsplash/Brigitte Tohm

We hope you find these products useful! Swirled may be compensated when users click on the affiliate links in the story below.

It doesn’t look like the keto diet is losing steam anytime soon. Celebrities are screaming about it, experts are writing books about it and folks who have tried it are sharing how amazed they are by their weight loss results. So, for everyone who is going keto (or seriously considering it), here’s one critical thing you need to know:

If you don’t maintain a state of ketosis, you’re not technically following a keto diet.

We know — crazy, right? Those super strict macronutrient ratios are provided for a legitimate reason. Basically, if you end up consuming too many carbohydrates (even by a tiny margin), then your body won’t receive the memo to derive energy from ketones (the result of digested fats) rather than glucose (the result of digested carbs). And we’ll be the first to acknowledge that counting your macros at every single meal and ensuring that all of your numbers fall in the exact ranges you need is a pain in the ass.

While bad breath, weight loss, appetite suppression and short-term fatigue can all be personal indicators that you’ve reached that coveted state of ketosis, they can’t be measured empirically and at a moment’s notice. If you really want to confirm that your keto diet is doing exactly what you’re asking it to on a biological level, here are the three ways you can find out.

Unsplash/Rachel Lynette French

Check Your Breath

Breath-based ketone monitors are probably your most expensive option, but they’re also the most convenient, least invasive and most accurate. They function similarly to an alcohol breathalyzer, except that they measure the ketone contents of your breath. You can test your ketone levels as many times in a day as you’d like, and a lot of monitors have Bluetooth connectivity capabilities so you can consistently track your ketone levels over time in an app on your phone. As long as you read between 8 and 40 parts per million (PPM) when you use the monitor, you’re in ketosis.

Check Your Blood

Just like how a diabetic checks their blood glucose levels, you can check the ketone levels in your blood (beta-hydroxybutyrate ketones specifically) with a finger prick and blood-testing kit. You probably won’t feel like doing this super often because that would make for a lot of sore fingertips and the refill strips do add up price-wise, but this testing method is super accurate. If you’re in ketosis, your blood ketones will be in the 0.5 to 3 millimoles per liter range.

Check Your Urine

Finally, you can use urine-testing strips to determine the levels of acetoacetate (another type of ketone) that your body is actively producing. This method is definitely the easiest option for beginner keto dieters, as well as the most affordable. Most look like the litmus tests you used in high school chemistry class to determine the pH of a particular substance. Simply pee on a strip, wait for 15 to 20 seconds and watch the color of the strip change. The darker it is, the more ketones you have, and the range on your specific testing kit will tell you whether or not you’re in ketosis.

However, if you’re on the keto diet for a while, your body will adapt to excrete fewer ketones via urine, which could result in a false reading. At that point, you’re better off using a blood or breath test instead.

Sign up for Daily Fit by Swirled, our newsletter featuring a wellness tip of the day and must-read health news from around the web! You’ll be one step closer to living a healthy, balanced life.

How To Know If You Have The Keto Flu (And What To Do About It)

11 Keto Recipes That Are The Opposite Of Diet Deprivation