Exogenous ketones are ketones that come in the form of a powder that you mix with water to drink them. Exogenous ketones are controversial in the keto world. The problem is the marketing of them have made some people believe that all they have to do is use this product to get into ketosis. If your blood glucose is too high your body will not use the ketones and they will go to waste.
Human's ability to produce and oxidize ketone bodies arguably evolved to enhance survival during starvation by providing an energy source for the brain and slowing the breakdown of carbohydrate and protein stores (Owen et al., 1967; Sato et al., 1995; Marshall, 2010). The brain is normally reliant on carbohydrate as a substrate, being less able to metabolize lipids, despite adipose tissue representing a far larger energy store than muscle and liver glycogen. Therefore, during starvation, lipids are used for hepatic ketogenesis and, via ketone bodies, lipids sustain the brain. Endogenous production of the ketone bodies, d-β-hydroxybutyrate (βHB) and acetoacetate (AcAc), increases slowly, driven by interactions between macronutrient availability (i.e., low glucose and high free fatty acids) and hormonal signaling (i.e., low insulin, high glucagon and cortisol). Produced continuously under physiological conditions, blood ketone concentrations increase during starvation (Cahill, 1970), when consuming a “ketogenic” (low carbohydrate, high-fat) diet (Gilbert et al., 2000) or following prolonged exercise (Koeslag et al., 1980).
Yes — you read that correctly — 24 hours of intermittent fasting without any resistance training and these subjects were able to preserve more muscle mass than the subjects that ate fewer calories every day without fasting at all. This finding contradicts our common sense, but when we dig deeper into autophagy we can find the mechanism behind this result.
I also concluded that post by discussing the possibility of testing this (theoretical) idea in a real person, with the help of exogenous (i.e., synthetic) ketones. I have seen this effect in (unpublished) data in world class athletes not on a ketogenic diet who have supplemented with exogenous ketones (more on that, below). Case after case showed a small, but significant increase in sub-threshold performance (as an example, efforts longer than about 4 minutes all-out).
Let’s take a look at some of the facts and misconceptions about three of the minerals used to make ketone mineral salts: sodium, calcium, and magnesium. Potassium is very hygroscopic, meaning that it absorbs water very easily. Therefore, it is only feasible that it can be utilized in liquid formulations. Thus, one should be cautious if companies say they have potassium BHB salt powder in their product. I’d be very surprised if that’s actually the case.
Beta-hydroxybutyrate (BHB): Nutrition strategies that rely on carbohydrates always leave us needing more food. On the other hand, the ketogenic diet relies on and taps into your body’s stored fat for longer, more stable energy with no bonking. Many keto-lovers adopt this lifestyle because they love the mental clarity, focus, and productivity that they experience while in ketosis. Whether you’re full-time keto or not, our Perfect Keto is designed to support ultimate mental performance.
Compared to our other cellular gasoline (carbs), we can store an unlimited supply of energy from ketones in our body within our fat. When you’re reliant on carbohydrates, you’re forced to keep your tank partly full as we can only store just over 2,000 calories of glycogen from carbs. An empty carb tank results in carb-withdrawal symptoms from not being able to switch into a ketone or fat burning metabolism.
Ketone Salts: While the body uses and makes BHB ketones salts naturally, in supplement form ketone salts are synthetically (lab) made compounds that combine sodium (and/or potassium, calcium, or magnesium) with BHB. The salt is used to raise the pH and make things less acidic. Currently, all ketone supplements on the market are made from ketone salts. While they raise ketone levels, most people will only experience mild nutritional ketosis (~0.6-1.0 mmol/L).
This process can be used as a way to get you into ketosis more quickly, so you can transition gracefully into a ketogenic lifestyle or as a way to stimulate autophagy and fat loss. If you can’t go without fat for the full 3 day fast — it’s okay — you will still illicit many of the benefits of fasting by limiting your protein and carbohydrate intake.
The reason for testing after one hour was based on Prüvit’s “59-minute test”, which recommends testing ketones 45-60 minutes after taking the supplement (by the way, saying “59 minutes” instead of 60 minutes or 1 hour just sounds like another marketing gimmick to me). Kegenix Prime also promises “ketosis in 60 minutes” on its packaging. We carried out the testing at more or less the same time each day.
Caveat emptor: the following post doesn’t come close to answering most of these questions. I only document my experience with BHB salts (and a non-commercial version at that), but say little to nothing about my experience with BHB esters or AcAc esters. But it will provide you will some context and understanding about what exogenous ketones are, and what they might do for athletic performance. We’ll likely podcast about the questions and topics above and cover other aspects of exogenous ketones in more detail.
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