Curious about exogenous ketones, but don’t know where to start? Wondering what they actually do? Read on for a quick guide on ketones, exogenous ketones, and how this all fits into a Keto Diet.
As you might know, the Keto Diet is a low-carb, high-fat diet that shifts how the body metabolizes its energy-producing fuel. When carbs are restricted, the body breaks down fat, or fatty acids, and creates ketone bodies. These ketones are then used by the body for energy. The Keto Diet has been shown to provide many benefits and has been used clinically to help manage diabetes, a few types of cancers and Alzheimer’s.
The body uses two main types of ketone bodies during ketosis: acetoacetate and beta-hydroxybutyrate (BHB). Both of these are made by the liver, usually in periods of fasting or when the body is in ketosis. Acetone is another type of ketone, though it’s found less often in the body and cannot be used to produce energy. Because these are made by the body, they’re known as endogenous ketones.
The word exogenous means originating from the outside. So, exogenous ketones, as you might have guessed, are ketones that come in the form of supplements. Unlike the ketones your body makes on its own, exogenous ketones are introduced into the body via two main supplements, ketone salts and ketone esters.
Ketone salts contain BHB ketones that are bound either to an amino acid or a salt, such as sodium, calcium, potassium or magnesium. These usually come in powder form and are then mixed into a liquid before consumption. Do be mindful these will deliver these minerals as well as ketones and do contribute to your daily intake. One study of 10 healthy male participants found that ketone salts taken before exercise increased body fat oxidation but impaired performance during high-intensity exercise.
In ketone esters, the ketones are bound to a compound called an ester. These are usually delivered in liquid form. There are a few ketone esters out on the market, but the most common are D-BHB monoester and AcAc diester. While both can safely raise blood ketone levels, the D-BHB supplement has been used in research studies more often than the AcAc diester.
Most exogenous ketone supplements contain between 8 and 12 grams of ketones per serving. While they have been shown to elevate blood ketone levels, they don’t trigger the body to enter nutritional ketosis. In other words, they don’t force the body to create ketones on its own. That said, exogenous ketones are generally considered safe.
Why use exogenous ketones at all? Great question. For one, it’s a great fuel source. It delivers ketones that the body then uses for energy. Because of this, these may help to spare muscle breakdown. This can help you sustain workouts and feel more energized. Also, they may decrease your appetite, because they do supply energy. One study found that ketone esters may help lower the amount of ghrelin your body releases for a window of about two- to four-hours after consumption. Ghrelin is a hormone that signals hunger. With all of these benefits combined, exogenous ketones may aid body fat loss.
Keep in Mind
Exogenous ketones do contain calories, at approximately 4 calories per gram, which is the same amount of calories that protein and carbs provide. A typical serving may contain a little under 100 calories. Because their effects last only a few hours, you may need several doses throughout the day to keep blood ketones elevated. Exogenous ketones may help curb appetite, which helps to offset the calories they supply.
While only limited research suggests exogenous ketones may help alleviate some of the common side effects of the Keto Diet, including “keto flu” and digestive discomfort, they can be helpful, especially when first transitioning into the diet. As always, talk with your doctor or a registered dietitian to determine if exogenous ketones and the Keto Diet are right for you.
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