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July 5, 2022

Ketosis | Definition, Benefits, Risks, And Symptoms of this Growing Trend

Ketosis | Definition, Benefits, Risks, And Symptoms

Ketones and definition of Ketosis
photo courtesy of Pixaby

Ketosis refers to an elevation of ketone levels in the body. It is a metabolic state in which ketones become an important source of energy for the body and brain. It occurs when carb intake and insulin levels are low. Ketones are a potential fuel source for the body that are increased when the body converts from burning sugar to fats.

Generally, the body uses blood sugar for fuel.  Glucose is a sugar and the primary sugar and fuel source for the body. Ketones which are produced from fats can be used as an alternative fuel for the body and brain, however. Getting into ketosis is not easy to do and requires a plan which we will get into down the road.

Why burn ketones?

There are potential health benefits to burning ketones over glucose and these include weight loss, management of type 2 diabetes, prevention of seizures, and even management of certain cancers.

Following a diet or nutrition program to get into ketosis can be very challenging and may not be for everyone. Keto diets are usually high in fat. For example, 20% of the calories may be protein, 10% may be carbs, and 70% may come from fat. The typical American diet consists of 45% to 65% calories from carbohydrates, 10% to 15% from protein, and 20% to 35% from fat.

This article explains all you need to know about ketosis, its purported benefits, its risks, and the symptoms associated with it.

What is the Definition of Ketosis?

Ketosis is a metabolic state in which your blood has a high concentration of ketones with beta-hydroxybutyrate being the most common one.

Ketosis begins when your body starts using fat as its main fuel source by reducing the availability of glucose or blood sugar. Getting into ketosis is accomplished by fasting, eating a very low carbohydrate diet, and even starvation (a more prolonged form of fasting) or some combination.

Insulin is a fattening hormone and is produced in response to the ingestion of sugars and carbohydrates. By lowering sugar and carbohydrate intake, insulin levels decrease enabling the body to burn calories from fat. Fatty acids are smaller units of fat that are oxidized (burned) in the liver and converted into ketones or ketone bodies which can be used as an alternative source of energy for the body.

Ketones cross the blood-brain barrier providing energy for your brain. Fatty acids do not cross the blood-brain barrier

To enter a state of ketosis, you may need to eat fewer than 50 grams of carbohydrates a day and maybe as little as 20 grams depending on your metabolism. The exact carb intake that will cause ketosis varies by individual.

How long does it take to get into ketosis?

It usually takes 3-4 days to achieve ketosis from a ketogenic diet though simply fasting for a day will get most individuals into ketosis within 24 hours

To achieve ketosis, you will want to increase the healthy fats in your diet and your intake of protein.

Healthy Fats

Healthy fats to include in your diet are monounsaturated fats and omega-3 fatty acids which are a type of polyunsaturated fats. These fats do not produce inflammation, do not suppress the immune system, and do not adversely affect cholesterol levels. Healthy fats decrease the risk of depression, too.

  • Monounsaturated fats include olive oil, peanut oil, avocado oil, and canola oil.
  • Omega-3 fatty acids include alpha-linolenic acid (ALA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA). EPA and DHA are found in fish oil.


Protein is found in nuts, plants, and animals. Leaner cuts of meat are healthier as they do not provide excessive saturated fats.

The best sources of protein include fish, chicken or turkey (skinless), whole eggs (yolk contains as much protein as the whites and nearly all the vitamins and minerals), milk, and whey protein powder. Supplements are a convenient way to obtain additional protein without excess calories from fats and carbohydrates. We recommend no more than two protein shakes a day. We prefer protein shakes rather than protein nutrition bars, which tend to have excess amounts of sugar.

What Not to Eat

pasta not on keto diet

But, sometimes it is easier just to remember what NOT to EAT.  You need to obviously remove or greatly reduce most carbohydrate-rich foods from your diet. This is the basis of the ketogenic diet. The carbs you need to restrict the most include:

  • grains
  • legumes
  • potatoes
  • rice
  • pasta
  • many loaves of bread
  • fruit
  • candy
  • sugary soft drinks and sugar-sweetened beverages (become familiar with the many names of sugar).
  • condiments and sauces that contain sugar, like ketchup or barbecue sauce.
  • food with artificial sweeteners.  Even though they may not contain sugar, the fact that they are sweet will trigger an insulin response – insulin is the fattening hormone.

To put this into perspective, 3 slices (96 grams) of bread contain roughly 45-50 grams of carbs, while 1 cup (186 grams) of cooked rice contains around 53 grams of carbs.

People may choose to follow a keto diet to lose weight, better manage their blood sugar levels, or reduce the incidence of epilepsy-related seizures, among other reasons.

Signs and Symptoms of Ketosis

How do you when you are in ketosis?  Below are some of the more common signs and symptoms.

  • bad breath which is caused by a ketone called acetone
  • weight loss
  • reduced appetite
  • headache
  • nausea
  • brain fog
  • fatigue

It’s common for a person new to ketosis to experience symptoms known as the keto flu, such as headache, tiredness, nausea, and stomach upset. These symptoms usually resolve in a week. Increasing water intake can minimize these symptoms.

How To Test Your Ketones When In Ketosis?

You can check your ketone levels using either a blood or urine monitor. Blood monitors are more accurate than urine testing. Keto blood monitors function much the same way as glucose monitors used by diabetics. If your blood ketones are between 0.5–3.0 millimoles per liter (mmol/L) you are in a state of ketosis. The higher that number, the higher your level of ketosis.

An even more accurate method to determine your level of ketosis is to use the glucose-ketone index or GKI. This requires knowing both your blood glucose and blood ketone levels.  There are monitors that will measure both simultaneously or you can use separate glucose and keto monitors. This link shows you how to calculate the glucose-ketone index. What you do is take your blood glucose levels and divide them by 18. Take the number and divide it by the ketone level.

If your glucose-ketone index is:

  • Less than 1 then you are in the highest therapeutic level of ketosis. ‘
  • Between 1 and 3, you’re in a high therapeutic level of ketosis which may be effective in the treatment of cancer, epilepsy, chronic inflammatory disease, and neurodegenerative diseases like Alzheimer’s and Parkinson’s.
  • Between 3 and 6 then you are in a moderate level of ketosis useful for managing type 2 diabetes, obesity, and insulin resistance.
  • Between 6 and 9 then you are in a low level of ketosis useful for weight loss
  • Above 9 then you are not in ketosis.

There is a misperception that one must eat a lot of meat to achieve ketosis. This is not necessarily true. One can achieve ketosis on a plant-based ketogenic diet.  Here is a link that discusses a plant-based keto diet or what is sometimes called ketotarian diet.

What are the Health Benefits of Ketosis?

There may be long-term health benefits to ketosis though not all experts agree on this.


Epilepsy is a brain disorder characterized by recurring seizures. It’s a neurological condition and affects 3 million adults in the United States and 470,000 children.

The ketogenic diet was developed in the early 1920s to treat epilepsy. It was known as early as 500 BC that fasting could help with the management of epilepsy.  The diet was developed to mimic the metabolism produced by fasting and was used initially to treat children with intractable epilepsy and was found to be effective.

Epilepsy is usually treated with medication but about 30% of epileptic patients continue to experience seizures throughout life despite drug treatment.

Weight loss

The ketogenic diet has increased in popularity over the last 20 years for its potential to create weight loss.

By keeping insulin levels low by consuming a very low-carb diet, the body switches over to the breakdown of fats leading to the production of ketones in the liver.  Burning more fat for calories leads to weight loss.

A ketogenic diet has the added benefit in that it increases satiety meaning it gives you a sense of fullness. You will feel less hungry with less tendency to overeat. This leads to higher levels of ketosis.

The real challenge to a ketogenic diet is it is difficult to adhere to over time. However, you do not have to eat a ketogenic diet every day if that helps with compliance. Some will eat keto 5 days a week and a higher carb diet two days a week or some other ratio.

There is one thing all successful diets or strategies used to lose weight have in common. They cut out the bad carbs (insulin spiking carbs), thus a ketogenic diet is not the only way to lose weight. Any type of low glycemic eating program will lead to weight loss.

Type 2 diabetes treatment

A ketogenic diet has been used to treat type 2 diabetes with success since it decreases the overall sugar load the body processes and metabolizes. Low insulin levels are the key to weight loss and lowering insulin levels is what the ketogenic diet is all about.

We recommend you work with a nutritionist if you have diabetes and are considering a ketogenic diet to avoid having your blood sugars go too low.

Ketogenic diets are also being studied in the treatment of acne, cancer, polycystic ovaries diseased, and neurodegenerative disorders like Alzheimer’s, Parkinson’s, and Lou Gehrig’s disease.

What are the Ketogenic Health Risks?

A ketogenic diet can present some side effects.

Some of the short-term side effects were mentioned earlier and include headache, fatigue, constipation, dehydration, and bad breath. These usually disappear within a few days or weeks of starting the diet.

The diet is also associated with a risk of developing kidney stones, elevated LDL or bad cholesterol, and nutrient deficiencies. The significance of the elevation in LDL cholesterol is frequently overstated. There are innocuous LDL (large fluffy particles) and there are atherogenic small LDL particles. A keto diet frequently leads to an elevation of the large fluffy not-harmful LDL particles. This can easily be determined by running an NMR lipid panel.

Kidney stones are the result of the extra protein from meat sources found in the ketogenic diet. This is maybe reduced by adhering to a plant-based ketogenic diet also known as a ketotarian diet. About 1 in 20 children with epilepsy who are managed with a keto diet will get kidney stones.

Nutritional deficiencies can occur because of the reduction in carbs but such deficiencies can be minimized by focusing on the consumption of green leafy vegetables and judicious use of nutritional supplements.

What’s more, the diet is highly restrictive. But one does not need to follow it every day. Many times a one-day “cheat day” where one consumes his or her comfort foods can make adhering to a ketogenic diet easier. Also, adopting a ketovegetarian diet will proved more options in food choices on the carb side.

It’s likewise important to note that there have been reports of ketoacidosis, but this is more of an issue in those who have diabetes. Diabetics should consult with nutrition before embarking on a ketogenic diet, as it may reduce their need for medication.

What is ketoacidosis? Ketoacidosis is a metabolic state triggered by excessive production of ketone bodies that causes metabolic acidosis leading to a change in the pH of the blood.

Low fiber intake is associated with a ketogenic diet due to the restriction on carbs. Fiber is largely found in fruits and vegetables. This can be avoided For this reason eating plenty of high fiber, low-carb vegetables to maintain good digestive health. Fiber prevents constipation. Strive for 35 grams of fiber daily.

More on Ketosis versus Ketoacidosis

The terms ketosis and ketoacidosis are frequently confused. Ketosis is largely good. Ketoacidosis is always bad.

While ketosis is a normal part of your metabolism, ketoacidosis is a dangerous metabolic condition sometimes fatal if not treated.

Ketoacidosis most frequently occurs in type 1 diabetics. In ketoacidosis, the bloodstream is flooded with extremely high levels of glucose and ketones making the blood acidic, which is life-threatening.  Insulin is needed to move sugar from the bloodstream to the cells. The lack of insulin in type 1 diabetics causes blood sugars to rise yet the body is unable to use the glucose since there is no insulin to drive the sugar into the cells. The body then starts producing ketones to provide energy for the body. Glucose levels are frequently 600 mg/dl in diabetics in ketoacidosis. The normal fasting blood sugar is 100 mg/dl.

Symptoms of ketoacidosis include:

  • excessive thirst or dry mouth
  • frequent urination
  • hyperglycemia, or high blood sugar
  • high levels of ketones in the blood (>3 mmol/L)
  • weakness
  • nausea
  • vomiting
  • confusion
  • difficulty breathing

If you’re experiencing any of these symptoms, seek immediate medical attention. Increasing water intake can minimize some of these side effects.

Who Should Avoid a Keto Diet?

Some people should avoid a keto diet or at least should obtain a physician’s clearance. Those who should discuss with a physician first before embarking on a keto diet include those with:

  • Kidney or liver disease
  • Gall bladder disease
  • History of gastric bypass
  • Muscular dystrophy
  • Rare metabolic disorders
  • Prone to kidney stones
  • Type 1 diabetes (not type 2 diabetes)
  • Pancreatic insufficiency
  • History of hypoglycemia
  • Pregnant or history of gestational diabetes
  • History of eating disorder
  • Mental health history
  • BMI under 20


Ketosis refers to the metabolic state in which the body converts fat stores into energy, releasing ketones in the process. You can achieve ketosis by following a ketogenic diet. Ketosis is a normal physiologic response to a low carb or low glycemic diet. A low glycemic diet is not necessarily low in carbs but consists of carbs that do not raise insulin levels very much.

Weight loss improved blood sugar management, and reduced seizures in children with epilepsy are recognized benefits of a ketogenic diet.

Short-term side effects of ketosis include headaches, stomach upset, and dehydration and they typically resolve in a week.

Long-term side effects may include kidney stones, increased LDL (bad) cholesterol, and nutrient deficiencies all of which can be dealt with safely.

To learn more about the keto diet check out our article, Keto Diet: Ins and Outs.


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Dr. Joe Jacko

Dr. Joe is board certified in internal medicine and sports medicine with additional training in hormone replacement therapy and regenerative medicine. He has trained or practiced at leading institutions including the Hughston Clinic, Cooper Clinic, Steadman-Hawkins Clinic of the Carolinas, and Cenegenics. He currently practices in Columbus, Ohio at Grandview Primary Care. Read more about Dr. Joe Jacko

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