How Long Does it Take to Get Into Ketosis?

Jan 18, 2019 17:03:00PM

If you’re feeling the urge to start keto, you may be anxious to know how long it will take for your body to start utilizing ketones, seeing results and becoming a fat-burning machine!

You may also be wondering if there are any ways to speed up the process. Or if there are things that will slow down your achieving ketosis, so you can avoid them!

Will it take weeks and weeks or even months? Or will it be an overnight thing?

Let's run through how long it generally takes to get into ketosis, if there is anything you can do to speed up the process, or if there are any side effects.

How Long Does It Take To Get Into Ketosis?

So, how long will it actually take you to get into this fat burning state, running on fat for fuel, and enjoying the extra energy, lower blood sugar, and reduced inflammation?

Some say that you can get into ketosis in as little as 12 hours. However, it will more likely take anywhere from 1 to 7 days and may take typically longer than that to see results depending on the respective metabolic starting point and previous lifestyle choices.

For those that are already healthy, active, and eating well, it could take less time than those that have been eating high amounts of sugar and other carbs. It takes a lot of effort to switch fuel sources so your body will take time to transition. Be patient!

Transitioning to ketosis is dependent on 3 important steps happening in the body:

  • 1. Glucose and Glycogen Stores Being Depleted

  • Our bodies can run on glucose or ketones for fuel. When we are eating a diet with carbs in it, our bodies run on glucose sourced from carbohydrates. When glucose is available, it will be the first to be used because it is the easiest to break down.

    Glucose that doesn’t get used immediately will get stored as glycogen in the liver or muscles. The body can only hold onto so much glycogen before it is sent into the more permanent and more spacious “storage unit” of fat!
    The first step of getting into ketosis is getting rid of all available glucose and glycogen in the liver and muscles.
    When we stop eating carbohydrates, blood glucose levels drop and our bodies turn to glycogen storage to help raise blood glucose levels. Once our bodies use up the stores of glycogen… it looks towards another source to fuel the body!


    2. Fats Being Broken Down

    When our bodies run low on sugars, our insulin levels drop and our body goes into “starvation mode”. During this time, our body reaches into our fat reserves for energy!


    3. Ketones Being Made

    In the liver, fatty acids are broken down into compounds called ketones. Ketones are the “body’s favorite way of transforming fats into easily digestible packets of energy.

    Your brain can’t absorb fatty acids, but it can absorb ketone bodies” (Rodio, 2018). Once your body is producing ketones, you will start using these for fuel.

    Once these three things happen, your body is in functioning in ketosis.


    Can You Speed Up the Process?   

    There are a few ways to get a jumpstart into ketosis. Trying these methods may speed up the process to get to your fat-burning and health goals!

    1. Fasting

    The fastest way to get into ketosis is by intermittent fasting
    “Fat fasting” is a more drastic measure to get into ketosis and should only be considered in rare circumstances. Fat fasting is eating about 80-90% of your calories from fat while keeping your total calorie count low (around 1,000 to 1,200 a day!)

    Fat fasting is one way to expedite the process of ketosis because glycogen stores are depleted quickly and the body is forced to burn fat.

    A fat fast is only recommended for those that are just starting keto for the first time or those that have experienced a 2 week (or longer) plateau. One should never fat fast for longer than five days as your body will actually begin to starve and will turn to muscle mass for energy.

    2. Exercising
    Fasting, combined with exercise, will quickly deplete your glycogen stores. With no incoming glucose and with high energy needs, the body quickly uses up the glycogen and prepares to break down fats.

    3. Limiting Carbs 

    By lowering your carb intake to about 20 grams or less per day, you will eventually start producing ketones. (Each individual is different, some can eat a higher carb count and still remain in ketosis.) 

    If you're looking for a way to make it easier to manage, you could try a keto meal delivery service!

    4. Increasing Fats

    The ketogenic diet is a high-fat diet. Make sure that you are getting about 70-80% of your daily intake from fat! For example, if you consume 2,000 calories a day, that would be about 144-77 grams of fat a day (Gustin, 2017).    


    Side Effects of Ketosis?   

    While discretion is advised, for most, eating low carb, conservative fasting, and exercising are perfectly safe methods to get into ketosis. However, when starting the ketogenic diet, some people experience the keto flu.

    These flu-like symptoms are due to the body adapting to a new diet of very little carbohydrates.

    “This drastic reduction can come as shock to the body and may cause withdrawal-like symptoms, similar to those experienced when weaning off an addictive substance like caffeine (Kubala, 2018).

    Some slide by the transition with no side effects, while others are plagued with nausea, diarrhea, headaches, muscle cramps, sugar cravings, etc. (Kubala, 2018).

    Typically, these symptoms will not last long and may be reduced through rest, hydration, and getting your carbohydrate limit through a high-base of vegetables and healthy fats.  

    How Do I Know if I’m in Ketosis?

    There are several different signs that your body is in ketosis:

    • Breath: Acetone is the smallest ketone produced as a by-product when fatty-acids break down. If you’ve heard of “keto breath”, this is why! When the acetone is produced during ketosis, breath smells metallic, fruity, or just… smelly.
    • Weight Loss: For those looking to shed a few extra pounds, this will probably be your favorite indication that you’re in ketosis. Some see dramatic weight loss in the first week, but that is typically just water weight. As you keep with it, the fat will start coming off as well.
    • Urine: If there are ketones in your urine, you are definitely in ketosis! You can test with a urine test strip.
    • Suppressed Appetite: When in ketosis, our appetites are suppressed by balancing blood sugar levels. Ketones impact cholecystokinin (CCK) a hormone that makes you full, and ghrelin, the “hunger hormone” (Asprey,  2018).
    • Keto Flu: As previously mentioned, flu-like symptoms are a common result of being in ketosis!

    • Blood: Ketones can appear in urine or blood. Testing ketones in blood are easily done through a blood ketone meter and are more accurate than a urine test.


    Final Thoughts:

    While the ketogenic diet may seem like a drastic change, especially compared to the traditional Western way of eating, it is relatively easy to get into ketosis and could be the key to your health and weight loss results you desire.

    If you’re trying to get into ketosis, but still want to enjoy delicious foods, follow our social media accounts for amazing keto-friendly versions of all your favorite foods from many professional chefs, bloggers, and recipe-developers!



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    I did the keto diet on the eve of my 60th birthday and lost 35 lbs over a period of about 3 or 4 weeks. I was never deep into ketosis (dark purple on the keto pee test strips). After getting back to (or near) my college weight (I eventually realized that at 60 I had more muscle mass than I had at 21), I stopped the keto diet and went back to eating whatever I wanted whenever I wanted (I don’t want sugar), but only gained back about 5 lbs in 3 years. Last December I did a 5-day water fast. Weight loss was not my goal, so I didn’t weigh myself. I was slightly into ketosis by the end of day 2, and deep into ketosis by days 3 through 5. One month later, I did a 34 hour fast and was deep into ketosis by the 24 hour mark. My goal is to train my body to have a more flexible metabolism, and based on my recent experience, I believe this is not such a difficult goal to achieve. For someone who has been eating healthy and has trained their body to be metabolically flexible, a shift from an insulin-based metabolism to ketosis within 12 hours seems totally possible.

    J. Gordon Spears

    I have never been in ketosis. I was on the old Atkins diet for years and never experienced ketosis. I am now into my fourth week of the keto diet and although I feel better and I am losing weight (I’ve lost 10 lbs.), I am still, at the most, at a moderate level on my ketone strips and in testing my blood.
    I am dedicated to the plan and don’t waver. I’ve read two Keto books, but still can’t figure out why I don’t enter ketosis.
    Again, I never have. ????


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