Ketones

Now and again someone will ask me about ketones. What are they, where do they come from, and how does the body use them. I will try to briefly explain what ketones are, how there are used, and how to test for them.

Ketones (ketone bodies) are byproducts of the liver as it breaks down stored body fat for energy. Fat is used for fuel once the glucose has been limited or used up. The human body, when given the choice, will burn sugar first and then fat. Note that the body can only hold a small amount of carbohydrate (sugar) compared to an almost unlimited amount of fat. When a person restricts their carb/sugar intake, blood sugar and insulin levels drop (a good thing) and the body will use up any glucose then look for an alternate fuel source. This is why we store fat. Stored fat can now be utilized to fuel all the body’s functions. Ketones become a fuel source when we sleep, fast, exercise, are starving, or when we restrict carbohydrates through a Ketogenic/LCHF diet.

When there is no alcohol or glucose available, the body looks at it’s stored fat
for fuel. The body will start breaking down fat for energy using a process called “beta-oxidation”. This process occurs at the liver and the end product are ketones. Once produced they are used to fuel the body and brain. The is an ever increasing body of scientific evidence that claims ketones are a superior fuel which burns cleaner than glucose. Again, think of ketones as a long, even burning log and glucose as kindling.

There are 3 types of ketones, acetoacetate, beta-hydroxybutyric, and acetone. Ketone bodies are formed during a process known as Ketogenesis. This begins with the breakdown of fatty acids into acetoacetate which is converted to Beta-hydroxybutyrate (BHB). BHB is technically not a ketone due to chemical structure but is considered one within the context of a ketogenic diet. The third type of ketones is acetone which is created due to a side effect of the production of acetoacetate. Acetone is the simplest and least used ketone. If not used quickly, acetone will breakdown and exit the body via the breath or urine. This causes the fruity smell of the breath which is referred to as “Keto breath”.

Glucose was not nearly as available in the past as it is now. Sugar in the volumes average humans consume today is roughly 25 times more than what it was 150 years ago. Before refrigeration, fruits and vegetables were only available seasonally. Sugar was a real treat mostly consumed by the rich. Ever wonder why the royalty of the 18th century were fat and had bad teeth? Animal protein was likely the main food source for the middle class and below. At times when food was scarce, boom! Ketones.

Now why don’t we look a some of the benefits of ketosis, using ketones for fuel. About 75% – 80% of the brain can use ketones for fuel. The other 20%-25% comes from glucose. Interestingly, this glucose can be produced by the liver meaning no dietary sugar is required or essential. There are NO essential carbohydrates! A brain using ketones performs better, brain fog is reduced or eliminated. I think this is why researchers/doctors are using ketogenic diets to treat alzheimer’s and dementia. Navy seals are experimenting with keto for deep sea divers as it ups mental alertness and focus. Short term explosive type exercise (sprinting, lifting, etc.) still needs some carbohydrate. For any exercise of more than 2 hours can be fueled using your stored fat via ketones. I’ve blogged about the benefits I experienced during my last Ironman race. Metabolic flexibility is truly amazing! Endurance activities can really take advantage of being fat adapted.

Measuring Ketones. Once you decide to become ketogenic, you’ll probably want to know if your body is producing ketones. Without testing you can probably be consider yourself in “ketosis” when your hunger disappears. Other indicators are improved energy levels, weight loss, and better sleep quality. Some of you will want to take this to the next level and test yourself for the presence of ketones in your body. There presently are 3 ways to do this; urine, blood, and breath. Ketones are measured in millimoles per liter (mmol/L). A normal healthy range for ketones in the body is 0.5 to 3.0 mmol/L. Urine can be tested using pee strips. When you are in ketosis for the first time, your body will over produce ketones and the extra are expelled in the urine. After being in ketosis for awhile, your body becomes better at producing the ketones it needs and therefore there are fewer to expel so the pee strips can become ineffective. Since acetone is produced and expelled through the breath, ketones can be detected via a breathalyzer. Testers can be costly but it’s a one time buy. Lastly and I think the best, most accurate is blood testing. Testing for ketones is the same as testing for blood glucose using meters that are able to test for both. The benefit is that they are the most accurate results but the down side is the test strips can be quite expensive, 5 – 10 dollars a strip. I use an Abbott Freestyle Precision Neo.

Note: I think there are still people confused by Ketoacidosis and nutritional ketosis. Diabetics need to be aware of the dangerous condition of Ketoacidosis which is present when abnormally high concentrations of ketones are in the blood turning it acidic. This should not be confused with nutritional ketosis which you know is quite healthy and a normal function of the body.