Are Ketones Good or Bad? Keto Diet

ketones
Ketones can be good or bad, depending on how high the levels are and what is causing their production

Ketones are substances your body produces when it burns fats for fuel instead of burning glucose. The fats get broken down into fatty acids, which then turn into ketones. This usually occurs when people are ill or fasting.

If you have diabetes, a high level of ketones in your body can lead to a serious condition called diabetic ketoacidosis (DKA).

However, if you are on a ketogenic (keto) diet because you’re trying to lose weight, ketones help provide your body with energy. During the initial days when your body is getting used to burning fats instead of sugars, you may experience unpleasant side effects often referred to as “keto flu.”

What is a ketogenic diet?

A ketogenic diet is primarily used for weight loss where you eat more fats and fewer carbs. Carb intake is typically restricted to 50 grams a day to as little as 20 grams a day, requiring you to eliminate such things as grains, candy, pastries, potatoes and sugary soft drinks from your diet. The goal is to shed pounds quickly by depleting the body of glycogen and water.

In the long term, a keto diet suppresses appetite, which leads you to consume fewer calories and thus maintain your desired weight.

Potential cons of a keto diet are:

  • Constipation, which comes with a low fiber, high-fat diet.
  • Stress on the kidneys and liver.
  • Keto flu
  • Being prone to nutritional deficiencies

What is ketosis?

Eating a keto diet is usually done with the aim of encouraging your body to reach ketosis. Ketosis is a metabolic state that occurs when your body doesn’t have enough sugars to burn for energy so it burns fats instead. 

When eating an extremely low-carb diet, your insulin levels go down. This causes the release of fatty acids into your bloodstream. Many of these fatty acids are transported into your liver where they are converted into ketones as a source of energy. This leads to a high concentration of ketones in your blood.

Glucose is also the main source of energy for your brain. So when you follow a low-carb diet, a larger portion of your brain will use ketones for energy as well.

Although ketosis is most often associated with ketogenic diets, it can also occur with:

What is the difference between ketosis and ketoacidosis?

There is a big difference between ketosis and ketoacidosis:

  • Ketosis is a natural metabolic state and is generally harmless. 
  • Ketoacidosis is a life-threatening metabolic condition that needs immediate medical attention.

While high levels of ketones should be fine if it's due to your keto diet, it’s not good if it’s due to ketoacidosis. In diabetic ketoacidosis, high levels of ketones cause blood to become highly acidic, which can be very dangerous.

What causes ketoacidosis?

Ketoacidosis is typically seen in people with diabetes, particularly uncontrolled type I diabetes. Diabetic ketoacidosis can occur when someone with diabetes:

  • Misses an insulin dose
  • Works out intensely while having high ketone levels and high blood sugar levels
  • Suffers from an infection like the flu
  • Abuses alcohol

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References
Hecht M. Ketosis vs. Ketoacidosis: What You Should Know. Healthline. https://www.healthline.com/health/ketosis-vs-ketoacidosis

Mayo Clinic. Diabetic Ketoacidosis. https://www.mayoclinic.org/diseases-conditions/diabetic-ketoacidosis/symptoms-causes/syc-20371551

Mehta A, Emmett M. Fasting Ketosis and Alcoholic Ketoacidosis. UpToDate. http://www.uptodate.com/contents/fasting-ketosis-and-alcoholic-ketoacidosis?source=search_result&search=ketosis&selectedTitle=1~150