How Long Does It Take to Get into Ketosis?

minute read | Last update: Nov 30th2022

This article is backed by studies and reviewed by a certified dietician.

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You’re eager to start the keto diet to accelerate your weight loss efforts. You’ve heard that to lose weight, you need to enter a state of ketosis. How long into your diet will it take for ketosis to occur?

By consuming 50 grams or fewer of carbohydrates per day, you may enter ketosis in two to 10 days. For some people, it happens more quickly, while for others, it can take longer. Your diet, metabolism, age, and level of physical activity all play a role in the speed at which you enter ketosis.

If you’re new to the keto diet and you want to maximize its efficiency, this is the article for you. Ahead, we’ll go in-depth on what it means to be in ketosis, how long it takes to reach that state, how to stay there, and how you know when you’re in ketosis. Keep reading!

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What Does It Mean When You’re in Ketosis?

Before we get into how long it takes to enter ketosis, let’s make sure you’re clear on what’s happening to your body when you’re in ketosis.

Ketosis is a fat-burning process that occurs during a carbohydrate deficit. Your body usually burns a type of simple sugar known as glucose, using it for energy. Glucose comes from our cell walls as well as the foods we eat. The more sugar and carbs in a food, the more glucose you flood your body with.

The problem is that your body doesn’t need nearly as much glucose as you give it, so you hold onto it for later. The glucose undergoes a process called glucogenesis where it becomes glycogen. Then the glycogen goes to the liver.

By reducing carbs on the keto diet, your body has no glucose to burn for energy, so it begins using the glycogen stores in the liver. What happens when the glycogen runs out? Well, you need energy to live, so the body has to burn something.

Ketone bodies come from fatty acids in the liver. When ketone levels increase, fat becomes the new energy source since your body lacks carbs. Once you enter this stage, you’re officially in ketosis.

How Long Does It Take to Get into Ketosis?

Now that you know how ketosis works, we can take a closer look at how long it takes to enter this state of fat-burning.

To be in ketosis, your blood ketones must be over 0.3 millimoles per liter or mmol/L. On the shorter side, you may be able to enter ketosis in as little as two to four days. For others, it takes upwards of a week. The longest amount of time it may take to achieve ketosis is 10 days, so a little over a week.

Why Do Some People Enter Ketosis Faster?

Now that you’ve started tracking when you’re in ketosis (we’ll tell you how a little later), you’ve noticed that it takes you days longer than your friend to enter ketosis. Is it just that your friend has been on the keto diet longer?

That can have something to do with it, yes. Here are some other factors that determine how quickly you’ll enter ketosis.


As a reminder, on the keto diet, 10 to 20 percent of what you eat is supposed to be protein, five to 10 percent should be carbs, and 70 to 80 percent is fat. On a diet of 2,000 calories per day, that’s between 40 and 50 grams of carbs, 75 grams of protein, and 165 grams of fat.

By ingesting so few carbohydrates per day, you’ll be more likely to enter ketosis faster compared to someone who isn’t tracking their carbs as closely. As you may recall from the blog, there is indeed a difference between net carbs and total carbs. Net carbs take into account just the carbs listed on a food ingredients list. Total carbs incorporate sugars, dietary fiber, and starches as well.

Fat Adaption

Those on the keto diet who enter ketosis in as little as two days, sometimes even sooner, are fat-adapted. What does this mean? When you’re fat-adapted, your body knows how to burn fat as an energy source almost as effectively as it does glucose.

To become fat-adapted, you typically have to have done the keto diet several times, maybe even many times. Other diets that require your body to use fat for energy can also make you more fat-adapted, including intermittent or longer-term fasting.

How do you increase your fat adaption? First, you need to enter a state of ketosis. Then you must maintain ketosis over the long-term, anywhere from four to 12 weeks. If you’re more athletically inclined, you might become fat-adapted sooner according to a slew of research. Those studies include this 2004 report from the Annals of Internal Medicine and this 2019 publication of the journal Sports.

Being fat-adapted and entering a state of ketosis is not the same. At the beginning of your keto journey, if you’ve never fasted or restricted carbs before, then your body will be used to burning carbs. Compared to other energy sources like fat, your body would rather burn carbs.

So you have to train your body out of a process it’s done for decades. In the early stages of ketosis, this is a careful balancing act. If you have a cheat day, spend an afternoon on the dirty keto diet, or otherwise eat more than 50 grams of carbs, you’re out of ketosis and will have to start all over to become fat-adapted.

Although fat adaption is not an easy state to attain, it’s worth doing, as you may see more pronounced results when on the keto diet compared to someone who isn’t fat-adapted.


The faster your metabolism, the easier it is for your body to process and digest the foods you consume. Lots of factors can determine the speed of your metabolism, including the following:

  • Being chronically stressed
  • Skipping meals or pushing mealtimes back
  • Staying up all night
  • Taking some medications
  • Being warmer than 75 degrees Fahrenheit, as your body produces less brown fat, the insulating fat that torches calories to keep you warm
  • Calcium deficiencies
  • Consuming too much caffeine
  • Not drinking enough water
  • Choosing sea salt over iodized salt
  • Hormonal shifts
  • Genetics


Although seniors can still enter ketosis, anticipate that it will take between seven and 10 days. A younger, healthier individual might go into ketosis sooner.

Physical Activity

The more active you are on the keto diet, the better you boost your chances of entering ketosis quickly. As you exercise, you use up your energy, which means you’re torching both glucose in the body and the glycogen stored in the liver.

How Long Does It Take to Lose Weight in Ketosis?

You’ve decided through the information in this article to start the keto diet. How many pounds should you expect to drop and when?

Weight loss through keto can start within the first week of the diet, but it depends. The factors above will influence how much weight you lose. The closer you adhere to the rules of the keto diet, the better. You want to exercise between three and five times per week, incorporating cardio and weight training into your routine.

At the very least, you’ll lose two pounds, but it can be as many as 10 pounds. That’s after a week on keto! On a non-keto diet where you exercise and restrict calories, weight loss happens at a much slower rate, about one to two pounds per week.

So why such a drastic difference in numbers on the scale? As you start the keto diet, you’re burning water weight, which is the spare water your body retains. Water weight tends to be centralized at the arms, legs, and midsection, leading to puffiness and bloating. Depending on how much water you’ve consumed today, water weight might add two to four extra pounds to your overall weight.

Okay, so what does that have to do with keto? Well, glycogen molecules are partially water. There are three grams of water per gram of glycogen. The more glycogen you have stored in the liver, the more water weight. Thus, when you burn through that glycogen in ketosis, the water weight is the first to come off.

Once the water weight is gone, you’ll have to be patient to see more weight loss results. About 90 days into the diet, you could lose 30 pounds of fat. This will make a big difference in your physique!

We do want to say this: everyone is different. The weight loss results above are just a guideline and not necessarily what will happen for you. You may find that once you start keto that you lose more weight or perhaps less.

How Do You Know When You’re in Ketosis?

Being in a state of ketosis is a huge part of your success on the keto diet, but how do you know when you’ve entered ketosis? Will you feel different? Look different?

You’ll definitely notice a few side effects, some of which are good, and others not so much.

Here’s a list:

  • Keto Insomnia, which should abate once your body gets used to the diet, so in a few weeks
  • Trouble with digestion, including diarrhea and constipation; these side effects also go away as the diet progresses
  • Fatigue at the beginning of the keto diet since your body has fewer carbs and thus less energy
  • Better energy and focus once your body adjusts to the new diet
  • Reduced appetite compared to your pre-keto days
  • Rapid Weight loss
  • Breath changes, which can include a fruity or unpleasant odor due to high ketone levels

The problem with the above side effects is that some people experience them all and others none or just one or two. You’re much better off determining if you’re in ketosis with tests.

One such test is a ketone meter. This blood test reads your beta-hydroxybutyric acid or BHB levels. The higher the BHB, the greater the likelihood you’re in ketosis.

The second type of test is a keto urine test. If you’ve ever taken a pregnancy test, this urine test works in much the same way. You either urinate on a strip or urinate in a cup and then hold the test strip in the cup for 15 seconds.

The testing strip will turn a certain color. Depending on the color you see, your ketone levels are low, moderate, or high.

You can also try a breath test. With this test, just exhale deeply and the acetone levels in your breath will indicate how many ketones your body is currently producing.

How Long Do You Stay in Ketosis?

Once you’re in ketosis, how long can you stay there? That’s really up to you. If you can maintain the keto diet and a good exercise regimen for an extended period, especially if you’re trying to lose weight, then you can stay in ketosis for as long as it’s possible. Some people have an easier time with long-term ketosis while others may not be able to do it.

Keto cycling could help. On a keto cycling diet, you alternate between keto days and days where you eat more carbs. Some proponents of keto cycling say you will see similar results to an all-keto diet. What’s certain is you can follow a keto cycling diet for long periods, between 30 and 90 days.

Tips for Getting into Ketosis

Have you tried the breath test, the urine test, and the blood test but you’re still not in ketosis? The following tips might be all you need to finally get over the ketosis hump and start burning more fat!

Use MCT Oil

Medium-chain triglyceride or MCT oil is a great way to get your blood ketone levels up, which means entering ketosis faster. Our MCT oil softgels are dairy-free, gluten-free, and non-GMO. A bottle contains 1,500 milligrams of MCT in 60 capsules.

Keep Exercising

As we said before, when you go through your body’s glycogen supply, you can begin burning fat. Exercise is a fantastic way to deplete glycogen. There’s no need to exercise daily though, as you risk burnout, fatigue, and injury.

Reduce Carbs Even Further

The keto diet is already low-carb, so what’s wrong with going low-low-carb? If you can, instead of consuming 40 to 50 grams of carbs per day, set a limit of 20 or 30 grams of carbs. The next time you test your ketones, you may find that you’re in ketosis!


Ketosis is a physical state in which your body burns fat for energy rather than glucose. Everyone who does the keto diet wants to be in ketosis, but it can take two to 10 days to get there. Being fat-adapted, exercising, and taking MCT oil can help you enter ketosis faster so you can begin losing weight on keto!

About the author

The Authentic Keto Team is here to bring you health tips that help you with losing weight fast. We focus on a clean keto diet for beginners because we believe that is the easiest and most simple way to healthy eating. Our keto weight loss tips will not only bring you into ketosis fast but will also help you to improve your mental health, sleep problems, and wellness.

- Our goal is to make keto success easy. -

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