What are ketone bodies and What is ketosis? Ketosis has recently become an extremely popular topic and receives both criticism and praise. Is being ketosis healthy or harmful? And if it is beneficial, should everyone do it?

This guide contains all the information you need about what ketosis is, how to get into ketosis, whether ketosis is healthy, what the effects of ketosis are, and whether ketosis is safe. This article indicates its benefits, potential risks and gives tips on how to successfully enter and stay in ketosis. In addition, you will learn what the symptoms of ketoacidosis are.

What is ketosis?

Ketosis is a metabolic condition in which the body uses fat and ketone bodies instead of glucose (sugar) as the main fuel source.

Glucose is stored in the liver and released as needed to obtain energy. However, after eating carbohydrates, it is extremely low for one to two days. Stocks of glucose are depleted. Your liver can make glucose from the amino acids in a protein that you consume in a process called gluconeogenesis, but not enough to meet the brain’s needs, because it requires constant fuel supply.

Fortunately, ketosis can provide an alternative source of energy.

In ketosis, your body produces ketone bodies at an accelerated rate. Ketones or ketone bodies are made by your liver from the fat you eat, as well as from your own body fat. The three ketone bodies are beta-hydroxybutyrate (BHB), acetoacetate and acetone (although acetone is technically the breakdown product of acetoacetate).

Even with a higher carbohydrate diet, your liver produces ketone bodies regularly (mainly while sleeping), but usually only in small amounts. However, when glucose and insulin levels fall on a carbohydrate restricted diet, the liver increases ketone production to supply energy to the brain.

When your blood ketone level reaches a certain threshold, you are considered to be in nutritional ketosis. According to leading researchers on the ketogenic diet (Dr. Steve Phinney and Dr. Jeff Volek), the nutritional ketosis threshold is a minimum of 0.5 mmol / L BHB (ketone body measured in the blood).

Although both fasting and a fat diet will allow you to achieve ketosis, only a ketogenic diet can be used for a long time. In fact, it seems to be a healthy way of eating that can be used indefinitely.

Does the brain need carbohydrates?

There is a belief that carbohydrates are necessary for the brain to function properly. Most dietitians asked how much carbohydrate an adult should eat will probably answer that it is a minimum of 130 grams a day. With this amount, you can be sure that your brain has a constant supply of glucose.

The truth is completely different. In fact, your brain will remain healthy and functional, even if you don’t eat carbohydrates at all. Thus, it is possible to maintain a diet without carbohydrates.

Although it is true that the brain has a high energy demand and requires some glucose. When your ketogenic diet is effective in your life, there are plenty of ketones that provide most of the fuel. Fortunately, your liver will always produce a small amount of glucose your brain needs, even in conditions of total hunger.

This system allowed our ancestors-hunters to stay without food for a long time, because they had access to a source of fuel at all times: stored fat.

In fact, the ketogenic diet has no negative effect on brain function. On the contrary. Many people think that they feel better mentally when their brain works mainly on ketone bodies.

And although your red blood cells and some kidneys require glucose, this can easily be provided by carbohydrate intake at keto level and / or gluconeogenesis. All other structures in the body can use ketones or fat instead.

Ketosis and its benefits

In addition to providing a sustainable energy source, ketones – and BHB in particular – can help reduce inflammation and oxidative stress, which is thought to play a role in the development of many chronic diseases.

Indeed, there are several guaranteed benefits and several potential benefits that dietary ketosis gives us.

Guaranteed Benefits:

  • Appetite regulation: One of the first things people notice in ketosis is that they are no longer hungry all the time. In fact, studies have shown that being in ketosis suppresses appetite. One study concerned people who lost weight on a ketogenic diet for eight weeks and then reintroduced small amounts of carbohydrates. Researchers reported that levels of ghrelin (‘hunger hormone’) were suppressed in people who remained in ketosis, while those who were no longer in ketosis had higher levels of ghrelin.
  • Weight Loss: Most people automatically eat less when they limit carbohydrates and are allowed as much fat and protein as they need to feel full. The ketogenic diet suppresses appetite, lowers insulin levels and increases fat burning. It has been shown that the ketogenic diet beats other diets designed for weight loss.
  • Reversal of diabetes and prediabetes: In people with type 2 diabetes or pre-diabetes, being in ketosis can help normalize blood sugar levels and insulin responses, leading to discontinuation of diabetes.
  • Potentially Increased Sports Performance: Ketosis can provide unusually long-lasting fuel delivery during prolonged exertion for both competitive and recreational athletes.
  • Seizure management: Maintaining ketosis using the classic ketogenic diet or the less stringent modified Atkins diet (MAD) has been shown to be effective in controlling epilepsy in both children and adults who do not respond to anti-epileptic drugs.

There is also exciting early research suggesting that ketosis may be beneficial for many other conditions, such as reducing the frequency and severity of migraine headaches, reversing PCOS, perhaps enhancing conventional brain cancer therapies, probably slowing the progression of Alzheimer’s disease, along with potential helping people live longer and healthier.

Nutritional ketosis and ketoacidosis

Nutritional ketosis and diabetic acidosis are completely different conditions. While nutritional ketosis is safe and beneficial to health, the latter is a medical emergency.

Unfortunately, many health professionals don’t really see the difference between the two conditions.

Ketoacidosis mainly occurs in people with type 1 diabetes if they don’t take insulin. In diabetic ketoacidosis (DKA), blood sugar and ketone levels rise to dangerous levels, which disturbs the delicate acid-base balance in the blood. People with ketoacidosis feel very sick and experience deep dehydration, vomiting, stomach ache and weakness. DKA requires hospitalization so that intravenous fluids and insulin can be given to gradually and safely lower blood sugar.

In nutritional ketosis, BHB levels usually remain below 5 mmol / L. However, people with diabetic ketoacidosis often have a BHB level of 10 mmol / L or higher, which is directly related to their inability to produce insulin.

This graph shows the huge difference in the amount of ketones in the blood between ketosis and ketoacidosis:

When the level of ketones in the blood rises above a certain level, the pancreas capable of producing insulin will release enough to shut down further ketone production. In contrast, the pancreas of a person with type 1 diabetes cannot produce insulin. Thus, if insulin is not injected or intravenously, the ketone bodies will continue to rise to life-threatening levels.

Other people who can potentially get ketoacidosis are people with type 2 diabetes who are taking drugs known as SGLT2 inhibitors (such as Invokana, Farxiga or Jardiance).

In addition, in rare cases, women who do not have diabetes may experience ketoacidosis while breastfeeding.

However, for most people capable of producing insulin, it is almost impossible to reach ketoacidosis.

Tips on how to put your body into a ketosis state

There are many ways to start a safe and effective diet, which is a carbohydrate-free diet.

  • Reduce your daily net carbohydrate intake to less than 20 grams: Although it’s possible that you don’t have to be so raw. Eating less than 20 grams of net carbohydrates each day practically guarantees achieving the state of diet ketosis. What does 20 grams of carbohydrates look like? Try our recipes that the ketogenic diet assumes. In addition, we’ll show you meal plans that limit carbohydrates to less than 20 grams a day.
  • Try Intermittent Fasting: Sticking for 16-18 hours without food can help you get into ketosis faster. This is easy to do by simply skipping breakfast or dinner, which often seems very natural, because the ketogenic diet is an appetite suppressant diet.
  • Don’t be afraid of fat: Eating a lot of fat is an essential and tasty part of ketogenic food! Make sure you find a source of healthy fat at every meal.
  • Cook with coconut oil: In addition to being a natural fat that stays stable at high temperatures, coconut oil contains medium chain fatty acids that can increase ketone production and can also help protect brain health and provide other benefits.
  • Exercise if possible: During the transition to ketosis, you may not have enough energy to engage in vigorous physical activity. However, moving on a brisk walk can make it easier to get into ketosis.

The effect of protein on ketose

Although it is clear that getting enough protein in the ketogenic diet is crucial to preventing muscle loss, many questions have arisen regarding its effect on ketone levels.

During digestion, the protein is broken down into individual amino acids that trigger the release of insulin. Although the amount of insulin needed to transport these amino acids to the muscles is small when large amounts of protein are consumed, the increase in insulin may somewhat reduce ketone production.

For this reason, ketogenic diets are limited by both proteins and carbohydrates, which ensures that ketone levels remain elevated.

However, the effect of protein on ketosis appears to be very individual.

Some people report that their ketone levels are much lower when they consume more than a small amount of protein. In contrast, others may be able to eat a lot of protein without any change in ketosis. For example, I did some experiments on myself to see how much protein I could eat and I still stay in ketosis, and found that ultimately it’s important to keep net intake below 20 grams a day.

Remember that every person is different and in your case this may not work. If you want to stay in ketosis and still eat a lot of protein, it may be a good idea to run your own experiments to determine your personal protein threshold.

What is optimal ketosis?

The range of nutritional ketosis is quite wide, as illustrated in the chart below.

Although nutritional ketosis begins with BHB levels of 0.5 mmol / L, the optimal ketone zone 1.5-3.0 mmol / L is thought to reflect maximum fat burning. Exercise can increase burning, but it is temporary and short-lived.

Some people may experience prolonged maintenance above 3.0 mmol / L after a ketogenic diet, but they are more commonly seen in starvation ketosis, which occurs after fasting for several days.

A blood ketone level of 10.0 mmol / L or higher indicates ketoacidosis, a medical emergency that requires immediate hospitalization and can be fatal if not treated quickly.

Importantly, BHB levels above 3.0 mmol / L did not show any additional benefit for weight loss or diabetes compared to staying in the ketosis nutritional zone.

In fact, some people suggest that persistent BHB levels above 3.0 mmol / L may indicate that the body is not using ketones effectively.

Furthermore, even if 1.5-3.0 mmol / L is considered optimal, achieving this BHB level is not necessary for weight loss and blood glucose control.

For example, in a recent study, patients who followed a ketogenic diet had average BHB readings just below 0.6 mmol / L. However, they lost an average of 12% of their body weight and experienced a significant decrease in blood glucose, which allowed them to discontinue antidiabetic drugs or significantly reduce their doses.

Stages of ketosis

The body must undergo several metabolic processes before it can increase ketone levels and adapt to keto.

Here is a brief overview of the stages that the body goes through, adapting to the limitation of fasting and carbohydrates.

Stage 1 – Glycogen depletion phase – 6 to 24 hours carbohydrate reduction

In this phase, insulin levels fall and glucagon levels rise. Glucagon lets the liver know that we need more blood sugar. As a result, the liver breaks down stored glycogen and increases gluconeogenesis.

Stage 2 – Gluconeogenic phase – 2 to 10 days reduced carbohydrates

During this phase, glycogen is completely depleted, and gluconeogenesis takes control of providing energy to the body.

At this point, the liver will begin to produce acetoacetate, which can spontaneously convert to acetone. This can cause a person to have a breath that smells like nail polish or paint thinner.

The time window for this phase is so wide (two to ten days) because its length depends on who fasts. For example, healthy men and obese people with a sedentary lifestyle tend to remain in the gluconeogenic phase for longer than healthy women.

Stage 3 – Ketogenic phase – after two days or less carbohydrate reduction

This phase is characterized by a reduction in the breakdown of proteins into energy and an increase in the use of fat and ketones. At this point you will definitely be in ketosis.

Each person will participate in this stage at a different pace, depending on genetic factors and lifestyle, level of activity, and how many times before they have fasted or reduced carbohydrates.

Stage 4 – Keto adaptation phase – after a few weeks carbohydrate reduction or it can last for several months

After a few weeks, the body will be at a deeper level of ketosis, and the ketone burning cells will be fully adapted to the new fuel source. The need for glucose will decrease to the extent that ketone bodies can provide up to 50% of the body’s energy requirements.

Here are four stages that everyone goes through while limiting carbohydrates. Whether you shun carbohydrates (ketogenic diet) or all foods, you’ll go through these stages.

Unfortunately, there is a great variety between individuals when it comes to the speed with which they go through these stages. Fortunately, your body will let you know if you’re on your way to ketosis. He will do this through some specific symptoms.

How will you know if you are in ketosis?

Technically, you are in ketosis if your blood ketone is 0.5 mmol / L or higher. However, there is no need to prick your finger to find out if you are in ketosis.

Pay attention to these physical symptoms that will tell you if you’re on the right track:

  • Increased urination: Keto is a natural diuretic, so you have to go to the bathroom much more often. Acetoacetate (ketone body) is also excreted in the urine and can lead to an increase in bathroom visits.
  • Dry mouth: Increased urination leads to dry mouth and increased thirst. Therefore, make sure you drink a lot of water and supplement your minerals.
  • Bad breath: Acetone is a ketone body that is partly excreted in our breath. It may smell sharp – like overripe fruit or nail polish remover. This is usually temporary and will pass after a week or so.
  • Reduced hunger and increased energy: Usually, after going through keto flu you will experience a much lower level of hunger and a clean or aroused mental state.

The above symptoms of ketosis will not tell you clearly what your ketone levels are, but they will give you the answer to the question “Am I in ketosis?”

If you experience all these symptoms, you are almost certainly in ketosis. If you experience one or two of these symptoms (such as increased urination or bad breath) you may not be in ketosis yet, but you are definitely on track.

On the other hand, if you want to know your exact ketone levels, you’ll need to draw some blood and use a blood ketone meter such as Optium Xido.

Ketone measurement

Here are three methods to check if you are in ketosis (listed in descending order – from the one that is considered the most difficult):

Measurement of ketone bodies in the blood

The blood glucose meter measures the amount of BHB in the blood. Ketone bodies in the blood are usually the lowest in the morning and at most a few hours after eating a ketogenic meal.

The scale for nutritional ketosis is as follows:

  • Light ketosis : 0.5 mmol / L – 0.8 mmol / L
  • Average ketosis : 0.9 mmol / L – 1.4 mmol / L
  • Deep ketosis : 1.5 mmol / L – 3.0 mmol / L

Levels above 3.0 mmol / L do not provide any additional benefit and may even indicate that ketones are not being used effectively.

Most people will be in light ketosis within two or three days of starting the ketogenic diet itself. It usually takes two to three weeks to get into deep ketosis. Deep ketosis is ideal for weight loss and can bring some neurological benefits that go beyond the benefits you get during light or medium ketosis.


Breathing ketone analyzers measure the amount of acetone in the breath using a color-coded system. For example, the Ketonix meter reflects the following levels of acetone:

  • Blue: you are not in ketosis
  • Green: mild ketosis
  • Yellow: moderate ketosis
  • Red: deep ketosis

Ketone bodies in urine

Ketone strips, or strips for measuring ketone bodies in urine, measure the amount of acetoacetate that is excreted in the urine. Any shade between light pink and purple means you’re in ketosis. The darker color means you are in deep ketosis.

However, dehydration can also cause urine stripes to become dark purple.

What’s more, checking if we have ketones in urine can be most helpful at an early stage, because the level of acetoacetate in urine may decrease after a few weeks of being in ketosis.

However, there is no need to go crazy about ketone measurements. Your success will not be determined by getting the most accurate ketone readings. The most important thing is that the ketogenic diet is properly followed by eating the right foods in the right proportions of macronutrients. This way you will be able to benefit from ketosis.

What if you are not in ketosis?

When the ketosis diet has no effects or symptoms – here are some strategies that can help:

  • Track carbohydrate intake: Although ketogenic therapy does not involve calorie counting, it can be helpful to record your carbohydrate intake to make sure you really eat less than 20 grams. Use an online application such as Fitatu for this purpose.
  • Test ketone bodies late in the morning or afternoon: Blood and urine ketones are usually lowest as soon as you wake up. Also, try to check them later, preferably a few hours after eating. Even if you will be in ketosis for only part of the day, you will still get some benefits.
  • Try to be patient: Although some people get into ketosis relatively quickly, it may take some time. Unfortunately, insulin-resistant people often have a longer trip. Bet on a solid month of eating keto and try to increase your physical activity if possible. In four weeks you should definitely be in ketosis and experience its benefits.

Ketogenic therapy – side effects, concerns and potential risks

Side effects usually occur within the first few days after the ketogenic diet begins in our lives and includes: headache, fatigue, dizziness, irritability, cramps and constipation. They are known as keto flu . They can be offset by, among others, fluid and electrolyte management.

Is being in ketosis safe for everyone?

Staying in ketosis is safe for most people and clearly provides many health benefits, including weight loss, optimal blood sugar and insulin levels, and improved attention span.

However, some people should only use a ketogenic diet under medical supervision, while others are best avoided.


Conditions requiring medical supervision and monitoring during ketosis:

  • Type 1 diabetes
  • Type 2 diabetes mellitus for insulin or oral antidiabetic agents
  • High blood pressure for medication
  • Liver, heart or kidney disease
  • History of gastric bypass surgery
  • Pregnancy

Conditions in which ketosis should be avoided:

  • Breastfeeding women
  • People with rare metabolic disorders that are usually diagnosed in childhood, such as enzyme deficiencies that interfere with the body’s ability to produce and use ketones.

Ketosis – the purpose of the ketogenic diet

Ketosis is a complex metabolic condition that has many unique benefits. The healthiest way to achieve ketosis is by following a ketogenic diet. If you want to get to ketosis even faster, try to implement some of the recommendations in this article. With these methods you can shorten your path to ketosis.

If you still have questions about the safety of keto and ketosis, write to me and I will try to help you.

In summary, ketosis is safe and beneficial to most people. This is one of the main reasons why the ketogenic diet is so effective at improving many different diseases.

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