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Ketosis is a normal metabolic process. When the body does not have enough glucose for energy, it burns stored fats instead; this results in a build-up of acids called ketones within the body.

Some people encourage ketosis by following a diet called the ketogenic or low-carb diet. The aim of the diet is to try and burn unwanted fat by forcing the body to rely on fat for energy, rather than carbohydrates.

Ketosis is also commonly observed in patients with diabetes, as the process can occur if the body does not have enough insulin or is not using insulin correctly.

Problems associated with extreme levels of ketosis are more likely to develop in patients with type 1 diabetes compared with type 2 diabetes patients.

Fast facts on ketosis

  • Ketosis occurs when the body does not have sufficient access to its primary fuel source, glucose.
  • Ketosis describes a condition where fat stores are broken down to produce energy, which also produces ketones, a type of acid.
  • As ketone levels rise, the acidity of the blood also increases, leading to ketoacidosis, a serious condition that can prove fatal.
  • People with type 1 diabetes are more likely to develop ketoacidosis, for which emergency medical treatment is required to avoid or treat diabetic coma.
  • Some people follow a ketogenic (low-carb) diet to try to lose weight by forcing the body to burn fat stores.

In normal circumstances, the body's cells use glucose as their primary form of energy. Glucose is typically derived from dietary carbohydrates, including:

  • sugar - such as fruits and milk or yogurt
  • starchy foods - such as bread and pasta

The body breaks these down into simple sugars. Glucose can either be used to fuel the body or be stored in the liver and muscles as glycogen.

If there is not enough glucose available to meet energy demands, the body will adopt an alternative strategy in order to meet those needs. Specifically, the body begins to break down fat stores to provide glucose from triglycerides.

Ketones are a by-product of this process.

Ketones are acids that build up in the blood and are eliminated in urine. In small amounts, they serve to indicate that the body is breaking down fat, but high levels of ketones can poison the body, leading to a process called ketoacidosis.

Ketosis describes the metabolic state whereby the body converts fat stores into energy, releasing ketones in the process.

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Some people follow a ketogenic diet as a way to lose weight.

Due to the fact that ketosis breaks down fat stored within the body, some diets aim to create this metabolic state so as to facilitate weight loss.

Ketosis diets are also referred to as:

  • ketogenic diets
  • keto diets
  • low-carbohydrate diets

The diet itself can be regarded as a high-fat diet, with around 75 percent of calories derived from fats. In contrast, around 20 percent and 5 percent of calories are gained from proteins and carbohydrates, respectively.

Adhering to the ketogenic diet can lead to short-term weight loss. A study conducted in 2008 and published in the American Journal of Clinical Nutrition found that obese men following a ketogenic diet for 4 weeks lost an average of 12 pounds during this time.

The participants were able to consume fewer calories without feeling hungry while following the diet.

Is ketosis healthy?

The ketogenic diet could have a healthful effect on serious health conditions such as:

  • cardiovascular disease
  • diabetes
  • metabolic syndrome

It may also improve levels of HDL cholesterol (high-density lipoproteins, also known as "good" cholesterol) better than other moderate carbohydrate diets.

These health benefits could be due to the loss of excess weight and eating of healthier foods, rather than a reduction in carbohydrates.

The ketogenic diet has also been used under medical supervision to reduce seizures in children with epilepsy who do not respond to other forms of treatment. Some studies have suggested that the diet could also benefit adults with epilepsy, although more research is required to confirm these findings.

However, longer-term adherence to the ketogenic diet does not appear to yield great benefit.

The American Heart Association (AHA), American College of Cardiology, and the Obesity Society have concluded that there is not enough evidence to suggest that low-carbohydrate diets such as the ketogenic diet provide health benefits to the heart.

Other conditions are also being studied to see if a ketogenic diet might be beneficial; these include:

In diabetic patients, ketosis can occur due to the body not having enough insulin to process the glucose in the body. The presence of ketones in the urine is an indicator that a patient's diabetes is not being controlled correctly.

Some dietitians recommend a ketogenic diet for individuals with type 2 diabetes, also known as non-insulin dependent diabetes (NIDDM). With type 2 diabetes, the body still produces some insulin but is unable to properly use the insulin to transport glucose into cells for use as fuel.

The ketogenic diet focuses on the reduction of dietary carbohydrate intake. Individuals with type 2 diabetes are recommended to reduce carbohydrate intake as carbohydrates are converted to glucose and increase blood sugar levels.

Patients with diabetes who follow a ketogenic diet need to carefully monitor their ketone levels. A serious condition called ketoacidosis can occur if these levels get too high, and although it is most prevalent in individuals with type 1 diabetes, people with type 2 diabetes can also develop ketoacidosis.

Ketoacidosis is a condition where the levels of ketones in the body are abnormally high, poisoning the body. It is a serious and dangerous condition that can quickly develop, sometimes within the space of 24 hours.

There are several different potential triggers for ketoacidosis. It is most commonly caused by illnesses that lead to the production of higher levels of hormones that work against insulin.

It can also result from problems with insulin therapy, either through missing scheduled treatments or not being given enough insulin. Less common triggers of ketoacidosis include:

  • drug abuse
  • emotional trauma
  • physical trauma
  • stress
  • surgery

Ketoacidosis most commonly occurs in people with type 1 diabetes due to the body not producing any insulin. Ketoacidosis can also occur in people with type 2 diabetes, although it is much less common.

High levels of ketones in the urine and high blood sugar levels (hyperglycemia) are signs of ketoacidosis and can be detected with kits in the home.

Early symptoms of ketoacidosis include:

  • abdominal pain
  • confusion and difficulty concentrating
  • dry or flushed skin
  • excessive thirst and dry mouth
  • fruity breath
  • frequent urination
  • nausea and vomiting
  • shortness of breath or rapid breathing

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Ketone levels can be monitored using urine testing kits that are commonly available over the counter.

Ketosis does not usually occur in healthy individuals that eat balanced diets and regular meals. Drastically reducing the amount of calories and carbohydrates that are consumed, exercising for extended periods of time, or being pregnant can all trigger ketosis.

In patients with diabetes, ketosis and eventually ketoacidosis may occur if insufficient insulin is used to properly manage the condition, if meals are skipped, or if an insulin reaction occurs (often while asleep).

Diabetic ketoacidosis is considered an emergency as it can lead to diabetic coma and even death. Treatment is usually administered by emergency healthcare workers, followed by hospitalization in an intensive care unit.

For diabetic patients, the following measures are commonly taken:

  • Fluid replacement - to rehydrate the body and dilute the excess sugar in the blood.
  • Electrolyte replacement - these are needed to help keep the heart, muscles, and nerve cells functioning correctly. Levels in the blood often drop in the absence of insulin. Electrolyte supplements are available to purchase online.
  • Insulin therapy - to reverse the processes that caused the episode of ketoacidosis.

Among otherwise healthy people, following a healthy, balanced diet and exercising regularly can prevent ketosis.