Ketosis is a metabolic state the body enters when it starts burning fat for fuel instead of glucose. Many people follow a ketogenic diet by restricting their carbohydrate intake because there are a variety of benefits of being in ketosis. If you decide to pursue the ketogenic lifestyle, chances are you’re serious about your health and want to be sure you’re doing the diet correctly.
There are four main ways to check whether you’re in ketosis:
- Ketone test strips, also known as “ketostix”
- Using a blood ketone meter
- Using a ketone breath analyzer
- Listening to your body
This article discusses how long it takes to get into ketosis and ways you can enter ketosis faster. It also covers each way to test ketosis in depth so you can decide which ketosis testing method is best for your lifestyle.
How long does it take to enter ketosis?
Most people’s bodies will enter a ketogenic state within anywhere between 48 hours and one week as long as they eat the recommended minimum of 20g carbs per day. Fasting and physical activity can both help speed up the process of getting into ketosis.
Ultimately, how long it takes to get into ketosis depends on your body and other lifestyle factors. You may be able to maintain a ketogenic state with more than 20g carbs, but everyone is different, so it’s best to start with 20g to ensure you’ll reach ketosis and then experiment with your carb limits.
How long does it take to get into ketosis if you fast?
Entering ketosis may take about 48 to 72 hours if you are fasting. This is the quickest method for entering ketosis because there’s no way to eat too many carbs if you don’t eat at all. Intermittent fasting (IF) is a less drastic measure that allows you to eat during a short window of time and still reap the fat-burning benefits of fasting. Many people combine IF with the keto diet for this reason.
The most common intermittent fasting schedules are 16:8 (16 hours of fasting and 8 hours of eating) and 18:6. Some intermittent fasters take it a step further by following a 23:1 schedule and only eating one meal a day (known as OMAD).
Using Ketone Test Strips to Check Ketosis
Ketone testing strips or “ketostix” are the least expensive way to check ketone levels in your urine. There is a fair amount of controversy around ketosix on reddit. In fact, you’re not even allowed to mention them on certain subreddits. The criticism of ketone testing strips is that they are not as accurate as a blood ketone meter. Ketostix don’t test ketosis; they test the amount of ketones excreted in your urine. Therefore, you may get a false negative if your body is using ketones effectively. You may also get a false negative if you drink a lot of water and your urine is very diluted.
Does this mean ketostix are totally useless? Absolutely not! They are a great starting point, and many people aren’t ready to invest in a ketone meter but can easily afford the testing strips. A 100-pack of Perfect Keto ketone test strips costs only $8.99 USD, and you can get 10% off your first purchase. There are also many other brands of ketostix on Amazon. Ketone testing strips are extremely easy to use; you just pee on them and then compare the color to the shades shown on the bottle. Darker pinks and purples indicate higher levels of ketones.
What color should your ketostix be when you’re in ketosis?
Having ketone levels between 1.5 and 3 mmol/L is considered to be optimal ketosis and is indicated by pink or dark pink on keto strips. Most people aim for this level of ketones for both weight loss and mental benefits. Achieving the higher levels of ketones indicated by dark maroon is not necessary. In fact, strips turning very dark may mean the ketones are concentrated in your urine because you are dehydrated.
If your strips are light pink for “trace ketones,” you may not achieve the maximum benefits of being in ketosis. You may want to try restricting your carbohydrates further. However, there is no reason to chase darker shades of pink on your keto strips if you are feeling great and seeing the results you want with trace ketone levels. Plus, you may only be seeing a lighter color because you are very hydrated and your urine is diluted.
It is important to note that if you use exogenous ketone supplements, your strip will turn dark, but this does not mean you’re truly in ketosis. It is a myth that using exogenous ketones is a way to enter ketosis. However, you may experience some benefits of ketosis while the ketones are in your system. Two brands of exogenous ketones I’ve tried and reviewed are Perfect Keto and Zhou Nutrition Keto Drive.
Using a Blood Ketone Meter to Test Ketone Levels
The ketogenic state can be tested by measuring beta-hydroxybutyrate (BHB) levels in the blood. A blood ketone meter is a device that allows you to do this at home. These devices also typically test blood glucose levels. Using a blood ketone meter is more accurate than using ketostix, but it’s also more expensive and requires you to prick your finger to get a blood sample. You insert a testing strip into the ketone meter and then add your blood sample to it. Plenty of people who follow the ketogenic lifestyle don’t own blood ketone meters, but they are cool for monitoring your ketone levels with accuracy if you like self-experimentation. Something to keep in mind is that although you only need to purchase a blood ketone meter once, you’ll have to continue replenishing the testing strips so you can keep checking your ketone levels.
Here are a few of the popular blood ketone meters on the market and their prices on Amazon:
- Precision Xtra Blood Ketone Monitoring Meter Kit – $81.00
- KETO-MOJO Blood Ketone and Glucose Testing Meter – $59.99
- Care Touch Ketone Testing Kit – $38.99
When you order your ketone meter, make sure that you order the test strips too if they aren’t included with the device!
Using a Breath Ketone Analyzer
If you don’t want to prick your finger to test ketones in your blood, you may prefer using a breath ketone analyzer. This reusable device works by measuring the amount of acetone in your breath. The ketone breath analyzer that dominates the market is the Ketonix. A major benefit of a breath analyzer is that it’s a one-time investment. With both ketostix and blood glucose meters, you need to regularly replenish your testing strips. However, the Ketonix is a bit pricey compared to the other options, with models ranging from $150 to $240. The Ketonix ketone breath analyzer is currently unavailable on Amazon (last checked 5/12/18) but can be purchased on the Ketonix website.
How can you tell if you’re in ketosis without testing strips?
You don’t necessarily need to buy ketostix or a ketone meter to check whether you’re in ketosis. There are also signs of ketosis you can look for just by paying attention to your body:
- Metallic taste in mouth: Many people notice a metallic taste in their mouths when they’re in ketosis. This is often referred to as “keto breath.” It’s caused by your body producing more acetone. Over time, keto breath may either go away or become less noticeable.
- Increased energy: One of the many reasons people follow a ketogenic diet is that they find it gives them more energy and greater mental focus. When you enter ketosis for the very first time, this energy boost is likely to be very noticeable.
- Carb cravings go away: When you first attempt a ketogenic diet, your body may still crave carbs. These feelings are likely to go away once your body starts burning fat for fuel.
- Water weight loss: Weight loss also many be a sign that you have entered ketosis. This is usually the result of your body releasing water weight. Weight loss is not a guarantee on the ketogenic diet as it is still typically necessary to eat at a caloric deficit for true weight loss. However, restricting carbs makes it easier for many people to avoid overeating because they may be more likely to binge on carbs than fat and protein.
While these signs can tell you whether you’re in ketosis if you listen to your body, it’s a good idea to at least use ketone test strips or a ketone meter to be sure you’re doing it right when you start out. Once you’re used to following a ketogenic diet, you’ll have a better understanding of how it feels when you’re in ketosis, and you won’t need to rely on ketone testing as much.
However, some people are susceptible to “carb creep” if they stop paying attention to their macros and don’t test ketones at all. Obsessively tracking your food is not vital on the keto diet. Over time, you may get used to how many carbs are in different foods and be able to eat intuitively, but occasional ketone testing helps keep you in check. There may be certain foods that throw off your blood glucose levels and kick you out of ketosis if you’re not careful with them, and testing is the best way to know what works for your body.
How do you check whether you’re in ketosis? Personally, I use Perfect Keto’s ketostix. Leave a comment with your thoughts!