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The Science Behind on How to Get Into Ketosis

Published on: August 22, 2019

The Science Behind on How to Get Into Ketosis

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Ketosis has received a ton of attention these days as more people desire to achieve long-term health, lose weight, and have more energy [1]. If you are interested in how to get into ketosis as well as the scientific explanation behind it, this guide is for you.

How Ketosis Works

You may think that ketosis is just like any other craze, but it’s not. Ketosis is a normal physiological state that you can induce by fasting or decreasing your dietary carbohydrates to 20-50 grams per day [2].

When you fast or limit your carbs for an extended period, your glucose reserves become depleted. To meet your energy needs, your body taps into alternative energy sources - ketone bodies, namely: acetoacetate, beta-hydroxybutyrate, and acetone. Ketone bodies are formed in the liver (through a process called ketogenesis) as a result of fatty acid breakdown. [2].

Ketone bodies cross the blood-brain barrier to provide the brain with clean energy. They also fuel your heart, skeletal muscle, kidneys, and intestines [3].

Bear in mind that nutritional ketosis is a temporary state, which means that you can remain in ketosis for as long as your blood ketone levels are within the optimal range. For nutritional ketosis, the range lies between 0.5 and 2 mmol/L. For starvation ketosis, the range lies between 5 and 10 mmol/L [5].


Factors Affecting Ketosis

Here are three factors that play a role in the induction of ketosis:

1. Glycogen availability

Consuming carbohydrates in the diet supplies your body with glucose, its primary metabolic fuel. Excess glucose is stored in the liver and muscles in the form of glycogen [6].

By limiting carbohydrates in the diet, your glycogen stores become depleted. This stimulates the production of ketone bodies. For as long as you stay within your carb limit, you remain in ketosis [6].


2. Insulin levels

When discussing ketosis, one should never miss mentioning insulin. Insulin is a hormone that is secreted by your pancreas, it regulates carbohydrate metabolism and how your body uses glucose. It is worth noting that insulin plays a significant role in the ketogenic pathway [7].

Decreasing dietary carbohydrate consumption reduces a person’s insulin levels. A state of low insulin leads to an increase in free fatty acids. When insulin levels drop, the availability of free fatty acids increases [7].

3. Free fatty acid availability

As the substrate used for ketogenesis, free fatty acids come from your stored body fat. Therefore, high circulating levels of free fatty acids enable your liver to produce ketone bodies [8, 9].


How to Get into Ketosis: 6 Scientifically Proven Tips to Get You There Quickly

Now that you know how ketosis occurs and the factors that contribute to it, you’re probably wondering how you can reach ketosis.

There is no one fastest way to get into ketosis because the timing can vary from person to person. It can take several days for some people to enter ketosis, while for others, it can take weeks. Factors that affect the length of time include your activity level, carbohydrate intake, and supplementation [10, 11].

Here are six things you can do starting today to transition into ketosis:

1. Limit carbohydrates in your diet.

Nutritional ketosis is done primarily by reducing dietary carbohydrates to limit the availability of glucose in your body. Ideally, only 5% to 10% of your dietary macronutrients should come from carbs. If you are following a 2,000-calorie per day diet, your carbohydrate limit will be 20-50 grams per day [6].

As the body’s main fuel source, carbohydrates can be found in nearly all the foods around you. These include most fruits, vegetables growing below the ground, grain food groups, fat-free or low-fat dairy, candies, soft drinks, and pastries [12, 13].


A study published by the Virta Health team revealed that the human body does not need dietary carbohydrates in order to thrive. While we know of carbohydrates to be the body’s primary source of energy, research shows that the body functions quite well on ketones. Beta-hydroxybutyrate, the body’s major ketone body, provides more energy than glucose [14, 15].

The only reason why our bodies crave carbohydrates is that it is what we conditioned it to crave carbohydrates because of our dietary choices [14]. That said, our bodies have this amazing capability to adapt to anything.

Another study showed that the theoretical minimal level of dietary carbohydrate intake is zero, and that there is no evidence of carbohydrate deficiency syndrome in humans [16].

It is also important to note that even in the absence of carbohydrates, your body is not completely deprived of glucose. The body synthesizes glucose from gluconeogenic precursors such as dietary protein, dietary triglyceride or adipose tissue triglyceride, and acetone [14].

2. Consider fasting intermittently.

Short-term intermittent fasting can speed up the process of keto-adaptation. In case you don’t know what intermittent fasting is, it’s a fasting method where you can only eat within a certain period (aka “eating window”).

There are plenty of ways to do intermittent fasting. One approach is to eat within 8 hours and go without food for 16 hours. This is called the 16/8 fasting method. Another approach, which is simpler for most people, is meal skipping. Breakfast is the easiest to skip.

Depriving yourself of food for at least 10 hours will force your body to break down its stored fat for energy. That’s when fatty acids are produced and broken down to form ketone bodies. Researchers also found out that intermittent fasting improves your sensitivity to insulin as well as your health biomarkers [17].

To make fasting work for you and not against you, pay attention to the quality of foods you eat within your eating window. Low-carbohydrate, high-fat, moderate-protein and nutrient-dense foods are the way to go.

Disclaimer: While there is scientific evidence to prove that intermittent fasting benefits people who are at risk for diabetes or have diabetes, medical supervision is a must. This is especially true if an individual is taking hypoglycemic medications.


3. Exercise more.

Exercise will deplete your glycogen stores, especially if you exercise while in a fasted state. Conversely, carbohydrate consumption can fully replenish your muscle glycogen stores [18].

Forssner first described Post-exercise ketosis in 1909. He found out that the acetone in his urine increased on days when he brisk walked in the morning [19]. Take note that acetone is one of the ketone bodies that are formed in ketosis.

Also, post-exercise ketosis that occurs in sedentary subjects can result from low carbohydrate intake. Athletes often consume starchy foods before an event to delay fatigue.

Study shows that high-intensity exercise of short duration led to the breakdown of glucose. Therefore, we can conclude that exercise intensity impacts ketosis. The more intense the exercise, the faster ketosis takes place [20].

4. Take supplements such as MCT oil and exogenous ketones.

Yes, there are supplements that can help you reach ketosis faster. They do so by increasing your ketone levels. Two popular supplements that induce ketosis are MCT oil and exogenous ketones.

You may have already heard of them, but how do they actually work? Are there studies to support their effectiveness?

MCT oil

Medium chain triglycerides or MCTs for short are a type of fat that is found in certain foods.

According to a 2018 study, MCT oil is considered ketogenic as it helps a person transition into ketosis easier by minimizing its symptoms (collectively known as keto flu). Also, MCT oil reduces the time it takes for a person to reach nutritional ketosis [11].

The same study revealed that MCT supplementation resulted in higher blood levels of beta-hydroxybutyrate, the major ketone body [11].


Exogenous ketones

Taking exogenous ketone drinks that contain ketone esters (KE) and ketone salts (KS) is a practical way to achieve ketosis. In a 2017 study, it was found out that between KE drink and KS drinks, KE drinks had a greater effect on beta-hydroxybutyrate levels than KS drinks by 50% [21].


5. Get adequate sleep.

You may not realize this, but your lifestyle choices, especially sleep, can affect your ability to reach ketosis. What happens when you lack sleep?

Sleep loss can impair glucose metabolism and increase your insulin levels, putting you at risk for Type 2 Diabetes. Remember that to achieve ketosis, you need to keep your blood glucose to healthy levels [22].

Other studies also suggest that sleep deprivation reduces your satiety levels and increase your appetite. This will likely explain why you to crave more carbohydrate-rich and sweet foods when you lack sleep [22, 23].

Here’s another thing you need to be aware of: The first few days of trying to enter ketosis are going to be difficult, and one of the symptoms you’ll experience is insomnia. There are various possible reasons for this:

One reason is frequent trips to the bathroom in the middle of the night due to increased urination since your body is depleting its glycogen stores. In case you’re not aware of it, approximately 65% of glycogen is water [24]. Another reason for insomnia is an electrolyte imbalance during keto-adaptation - for example, magnesium.

If you are experiencing poor sleep, interventions that will help you include doing meditation, avoiding caffeine late in the day, improving your bedroom environment, and taking a melatonin supplement.

6. Beware of hidden sugars in foods.

Hidden sugars can prevent you from achieving nutritional ketosis. Not just that, hidden sugars carry health risks. They add to your waistline, increase your risk of heart disease, and lead to metabolic syndrome as well as Type 2 Diabetes [25, 26].

You may be surprised to know that sugar hides in everyday foods. Examples include tomato ketchup, store-bought chocolate chip cookies, store-bought vegetable juice, instant oatmeal with added flavoring, soda, and pastries [26].

The fact that sugar has many guises is a solid reminder to be cautious with food labels. Be sure to scan the ingredients list and look for other names for sugar such as agave nectar, cane sugar, corn syrup, maltose, dextrose, and molasses [27].


How Do I Know If I'm in Ketosis?

While you apply the techniques to reach ketosis, how do you know that you are already in ketosis? You can watch out for common signs and symptoms or get actual data by testing your body’s ketone levels. Pay attention to the following:

1. Fast water weight loss

Before your body burns its stored fat, it uses up your stored glycogen first. Recall that glycogen is stored with water inside your muscle and liver cells [28].

This will explain why you are losing weight more rapidly in the first few days of pursuing ketosis. You will also experience increased urination as water gets eliminated by your kidneys.


2. Keto breath

People in ketosis will often complain of bad breath, commonly known as keto breath. This characteristic fruity smell comes from acetone, the least abundant ketone body. Due to its small size, acetone diffuses into the air spaces of your lungs [29, 30].

There are also times when you’re able to smell acetone in your sweat during a workout.

To deal with bad breath, be sure to practice good oral hygiene. Mask your breath with fresheners or sugar-free mints if you must.

3. Dry mouth and excessive thirst

Do you feel thirstier than usual? Is your mouth dry? This is an expected short-term effect of ketosis, and is a result of water loss and increased ketone production in the body.

While these symptoms are typical, never ignore them by increasing your water intake. If you don’t drink more water, you might experience dehydration, an electrolyte imbalance, headaches, and decreased energy [31].

4. A steady stream of energy

Ketone bodies are a rescue fuel during an energy crisis. In fact, study shows that ketone bodies yield more energy than glucose [32]. This is why your energy levels stabilize once your body becomes fat-adapted.

In ketosis, your blood glucose stays within the normal range, and you are less likely to experience sugar crashes or reactive hypoglycemia that result in decreased energy.

5. Better mental performance

When it comes to brain function, numerous research studies have shown that nutritional ketosis has neuroprotective and cognitive benefits in both human and animal subjects [33].

To be specific, you may describe this change in mental performance as better concentration, mental clarity and less brain fog. In a study involving aging mice, nutritional ketosis was shown to improve memory [34].


6. Urine testing

Urine testing is done to detect the presence of the ketone body acetoacetate. In a study that was conducted on 12 healthy subjects with stable ketosis, results showed that ketonuria can be most likely detected early in the morning and after dinner. Testing is usually done with the use of over-the-counter reagent strips [35].

You need to dip the end of a strip into your fresh urine sample, remove it, and wait for the color to change. You will compare the color against the color chart on the container bottle to determine the level of acetoacetate in your urine.

7. Breath testing

Earlier, we mentioned that acetone gives you that characteristic ketone breath. Like urine testing, breath testing to measure breath acetone concentration (BrAce) is a non-invasive way to detect ketosis.

A 2015 study showed that BrAce and the rate of fat loss in an individual are correlated. The same study also revealed that BrAce is strongly related to beta-hydroxybutyrate (BHB) levels since BrAce is sensitive to BHB [29].

8. Blood testing

The most surefire indicator of ketosis is the presence of ketones in the blood. Blood testing allows you to measure beta-hydroxybutyrate, the most abundant circulating ketone.

While this testing method is invasive and potentially painful, it produces more accurate results. Furthermore, blood ketone test strips have a longer shelf life [36].

Ketone levels within 0.5 to 2 mmol/L indicate nutritional ketosis. Ketone concentrations can further increase to 5 and 10 mmol/L (but lower than ketoacidosis) which indicate starvation ketosis [5].


We hope that these tips enter help you start entering a state of ketosis today. If you pay close attention, the strategies for achieving ketosis involve controlling your blood glucose, depleting stored glycogen, and raising ketones to safe, nutritional ketosis levels. Lastly, if you’re eager to get the most reliable readings for your journey into ketosis, invest in a ketone blood testing kit.


  • You can get in and out of ketosis anytime, which means that it is a transient state.
  • Ketosis is safe and provides your body with energy during starvation or low glucose supply.
  • Factors that facilitate or hinder ketosis include glycogen availability, insulin levels, and free fatty acid availability.
  • There are positive and negative signs and symptoms of ketosis which include fast weight loss, bad breath, increased thirst, better energy, and enhanced mental clarity.
  • Objective ways to measure ketosis include urine testing, breath testing, and blood testing.


  2. Paoli A et al. Ketosis, ketogenic diet and food intake control: a complex relationship. 2015 February 2 -
  3. ScienceDirect. Ketone Bodies.
  4. Castro J. What Is Ketosis?... View all references

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