Thank you, Mark! I am an ME/CFS patient, and I have improved quite a bit on a ketogenic diet, which I have been following for the past 3 months. I am slowly losing weight (much needed) and I wondered, does using exogenous ketones inhibit fat loss? I’m trying to balance the benefits of continuing weight loss with benefits in dealing with ME/CFS symptoms. Thank you for any info you can offer!
Effects of ketone supplementation on blood glucose. a, b Blood glucose levels at times 0, 0.5, 1, 4, 8, and 12 h (for 10 dose) post intragastric gavage for ketone supplements tested. a Ketone supplements BMS + MCT and MCT significantly reduced blood glucose levels compared to controls for the duration of the 4-week study. BMS significantly lowered blood glucose only at 8 h/week 1 and 12 h/week 3 (b) KE, maintained at 5 g/kg, significantly reduced blood glucose compared to controls from week 1–4. BD did not significantly affect blood glucose levels at any time point during the 4-week study. Two-Way ANOVA with Tukey’s post hoc test, results considered significant if p < 0.05. Error bars represent mean (SD)
Concentrations of plasma non-esterified fatty acids, triacylglycerol, glucose, and insulin following equimolar ketone ester and ketone salt drinks, at two amounts, in subjects (n = 15) at rest. Values are means ± SEM. (A) Plasma FFA. (B) Plasma TG. (C) Plasma glucose. (D) Plasma insulin at baseline and after 30 and 60 min. EH, ketone ester high; EL, ketone ester low; SH, ketone salt high; SL, ketone salt low. *p < 0.05 difference from baseline value.
Exogenous ketones can lower appetite during a fast. After an overnight fast, normal weight human subjects either drank a ketone ester supplement or a calorie-matched glucose drink. Compared to the glucose drinkers, the ketone drinkers had lower insulin, lower ghrelin, greater satiety, and less hunger. This can be useful for people trying to extend their fast who don’t want to or can’t yet deal with the hunger. You’re still taking in energy, but the metabolic profile remains similar to that of a fasted person.
Although decreases in FFA, TG and glucose occurred, there were no significant differences between the KE and KS drinks or with intake amount. Ingestion of ketone drinks significantly decreased overall mean plasma FFA from 0.7 to 0.4 mM, TG from 1.1 to 0.9 mM and glucose from 5.7 to 4.8 mM after 1 h (all p < 0.05). Concentrations were the same as at baseline by 4 h, with FFA at 0.6 mM, TG at 0.9 mM and glucose 5.1 mM (Figures 2A–C). There was a rise in insulin concentrations 30 min following all drinks, probably due to the small amount of carbohydrate in the sweetener (Figure ​(Figure2D2D).

Despite the recent growth of the ketone salt market, there is very little published work analyzing the effects of these products on any biomarkers or performance measurements in humans. Several studies have been carried out in rats,6,7 with blood BHB levels being relatively low (<0.5 mM) post-consumption of salt drinks. In humans, ketone salts provided peak D-BHB levels of 1 mM, whereas the same amount of BHB in a ketone ester (BD-BHB) raised blood BHB to 2.8 mM.5

Effects of ketone supplementation on blood βHB. a, b Blood βHB levels at times 0, 0.5, 1, 4, 8, and 12 h post intragastric gavage for ketone supplements tested. a BMS + MCT and MCT supplementation rapidly elevated and sustained significant βHB elevation compared to controls for the duration of the 4-week dose escalation study. BMS did not significantly elevate βHB at any time point tested compared to controls. b BD and KE supplements, maintained at 5 g/kg, significantly elevated βHB levels for the duration of the 4-week study. Two-Way ANOVA with Tukey’s post hoc test, results considered significant if p < 0.05. Error bars represent mean (SD)
Sometimes waiting for your body to make the switch from carbohydrate metabolism to beta hydroxybutyrate metabolism (aka ketosis) can be an uncomfortable and lengthy process. Another way to get beta hydroxybutyrate into your system so your body is using “clean” energy is by taking it supplementally or through nutrition. A betahydroxybutyrate supplement is what can be used in this scenario. This is an exogenous ketone. Exogenous means you get it from outside of your body. Think EX = exit = outside.
The classical KD consists of a 4:1 ratio of fat to protein and carbohydrate, with 80–90 % of total calories derived from fat [27]. The macronutrient ratio of the KD induces a metabolic shift towards fatty acid oxidation and hepatic ketogenesis, elevating the ketone bodies acetoacetate (AcAc) and β-hydroxybutyrate (βHB) in the blood. Acetone, generated by decarboxylation of AcAc, has been shown to have anticonvulsant properties [28–32]. Ketone bodies are naturally elevated to serve as alternative metabolic substrates for extra-hepatic tissues during the prolonged reduction of glucose availability, suppression of insulin, and depletion of liver glycogen, such as occurs during starvation, fasting, vigorous exercise, calorie restriction, or the KD. Although the KD has clear therapeutic potential, several factors limit the efficacy and utility of this metabolic therapy for widespread clinical use. Patient compliance to the KD can be low due to the severe dietary restriction - the diet being generally perceived as unpalatable - and intolerance to high-fat ingestion. Maintaining ketosis can be difficult as consumption of even a small quantity of carbohydrates or excess protein can rapidly inhibit ketogenesis [33, 34]. Furthermore, enhanced ketone body production and tissue utilization by the tissues can take several weeks (keto-adaptation), and patients may experience mild hypoglycemic symptoms during this transitional period [35].
Since beta hydroxybutyrate is transported throughout the body via the blood, the best way to check your true BHB levels is through a blood test. The good news is that you can just use a simple finger prick and an at home method that is very similar to how diabetics check their glucose. The bad news is that it can be pretty expensive. Each strip and time you test can be around $4-6.
MCT Oil is a keto supplement that helps your body make ketones. The oil contains pure medium-chain triglycerides (MCTs), which are types of fatty acids that your body prefers using for immediate energy. Unlike long-chain fatty acids, MCTs don't require enzymes and bile for digestion and they go straight to the liver where they are used for making free fatty acids or ketones. Studies on MCTs show that they promote weight loss [5].
It's also a smart idea to start slowly with this supplement. We can thank Dave Asprey for the term “disaster pants” which has been used by those who try MCT oil at too high a dose when they first start using it. There is a chance that you can experience the same unpleasant gastrointestinal effect with exogenous ketones if you start with too high a dose, or if you maintain a higher carbohydrate diet while using this supplement. Used in appropriate doses, it gets absorbed through your stomach into your liver, then sent out to the rest of your body.
If you noticed that you're not getting into ketosis quick enough, chances are you're not eating enough fat. Eating plenty of healthy fat is essential in inducing ketosis. One reason why this is so is that your body makes ketones from fat. The other reason being that fat is highly satiating, so your body won't slow down or start breaking down muscle for fuel.
Core BHB™ provides pure goBHB™ in an all-natural formula with no artificial sweeteners, making ideal for those on the keto diet, athletes, and people who are health-conscious. Even if you’re on a high-carb diet, Core BHB™ will rapidly elevate blood ketone levels and help your body enter a state of ketosis (often with 30 minutes of consumption). In turn, you will experience increases in energy, fat loss, endurance, and mental acuity. With regular use of Core BHB™, you can also speed up the transition from a higher-carb diet to the ketogenic diet and reduce symptoms of the “keto flu”.
If you’re somebody who isn’t already a keto-goer, then you might be wondering why? Why do I need to limit my carbohydrate intake to get my body into a state of ketosis? Simply put, and without getting to technical; you want your body to be in a constant state where fat is the is the primary source of fuel for the body rather than glucose. You see, once you eat carbs, the body will break this down into glucose which it will then use for fuel before tapping into your fat reserves for energy. If you limit the amount of glucose that is in your system by restricting your carbohydrate intake, the body has no choice but to tap into your fat stores for energy. Fats are metabolised in the liver where ketones are then produced for your physical and cognitive needs.
Since beta hydroxybutyrate is transported throughout the body via the blood, the best way to check your true BHB levels is through a blood test. The good news is that you can just use a simple finger prick and an at home method that is very similar to how diabetics check their glucose. The bad news is that it can be pretty expensive. Each strip and time you test can be around $4-6.

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 current USDA recommendations reflect “unachievable goals” that do not match what research suggests our normal physiological ranges might be[10]. There is not enough evidence to show that sodium restriction is associated with less mortality or cardiovascular morbidity in healthy individuals or individuals with high blood pressure, and there is evidence that sodium restriction might actually be harmful to individuals with heart failure[11]. For serious athletes, and individuals who are active daily, the current recommendations might not only be unwise but unsafe. If you are eating a carbohydrate-restricted diet, this applies to you even more. Don’t stress about the high amounts of sodium in a lot of these ketone supplements, being that they allow for a fast delivery of ketones to the body, which has unique benefits that will be discussed in a separate article.  Instead, change out the frozen dinner and experiment with an effective dose of exogenous ketones.
The human studies aren’t quite there yet, but it seems likely that they’d help. A recent human case study found that ketone esters added to the regular diet improved Alzheimer’s symptoms. Animal studies indicate that adding exogenous ketones to a regular lab (read: not ketogenic) diet can reduce seizure activity and improve overall symptoms in epilepsy animal models, reverse early neuronal hyperactivity in Alzheimer’s animal models, and reduce anxiety in rats.

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.
At baseline, 4 h after intragastric gavage, the elevation of blood ketones was inversely related to the reduction of blood glucose compared to controls following the administration of MCT (5 g/kg) (p = 0.008) and BMS + MCT (5 g/kg) (p = 0.039) . There was no significant correlation between blood ketone levels and blood glucose levels compared to controls for any other ketone supplemented group at baseline (Fig. 4a). At week 4, 4 h after intragastric gavage, there was a significant correlation between blood ketone levels and blood glucose levels compared to controls in MCT (10 g/kg) and BMS + MCT (10 g/kg) (p < 0.0001, p < 0.0001) (Fig. 4b).

Do you need carbs to train? No. Again this is an anecdote only, but I have done numerous training sessions in a carb deprived state. Heck some of my best training sessions where done in a fasted, carb deprived state. And there are a lot of endurance athletes who are using a ultra-low carb/ketogenic diet and putting up some great times (more on this below).
Ketones are an alternate energy or fuel source for brain and body that our bodies have naturally produced and used for millennia. Ketones have recently leapt to the forefront of health and wellness conversations worldwide as the scientific body of research that seeks to understand their numerous unique properties and profound systemic effects has begun to grow (see below).
For anyone who wants to get a bit more technical, research by Stubbs and colleagues shows that BHB shuts off lipolysis (fat breakdown). With endogenous ketosis there are many other factors that stimulate lipolysis meaning that a kind of balance is reached and lipolysis stays constant. But with exogenous ketosis those factors stimulating ketosis are not present, so the overall effect of the ingested BHB is to decrease lipolysis.
Your body uses the energy source that is the easiest to use, in our case this is glucose. Glucose is just a type of sugar. As our body cannot store glucose as such it stores the extra glucose in form of glycogen that is stored in our liver and muscles. To initiate production of ketones in your body as fast as possible you must deplete your body of glycogen reserves. The best way to do this is a simple 24 hours fast. This will deplete your glycogen stores as fast as possible. If you don’t over eat for dinner or you even skip it all together you will already wake up in state of mild ketosis the next morning due to the overnight fast. Here are also described some signs that you are in Ketosis already.
Some people follow more of an Ultra Low Carb diet approach. This is generally around 50g or less of carbs per day. A ULC is more supportive of reaching a ketogenic state, but again total carbs are not the only variable when it comes to reaching ketosis (other factors such as types of carbs, protein consumption, portion size, ingredients, supplements used etc. all play a role and will be covered in more detail below). 
Alright, first of all, I tried every combination available for this product. I really loved the idea of adding it to my morning iced coffee with MCT, 1 tbs of heavy cream and stevia. To be honest, my morning coffee is one of my favorite things throughout my day and I was very dissppointed when it didn’t taste *exactly* like an iced mocha. I found it to be very bitter and tough to finish. Not to mention it was ruining my love for my morning coffee time.

Ketone supplementation did not affect the size of the brain, lungs, kidneys or heart of rats. As previously mentioned, the rats were still growing during the experimental time frame; therefore, organ weights were normalized to body weight to determine if organ weight changed independently to growth. There could be several reasons why ketones influenced liver and spleen weight. The ratio of liver to body weight was significantly higher in the MCT supplemented animals (Fig. 5). MCTs are readily absorbed in the intestinal lumen and transported directly to the liver via hepatic portal circulation. When given a large bolus, such as in this study, the amount of MCTs in the liver will likely exceed the β-oxidation rate, causing the MCTs to be deposited in the liver as fat droplets [94]. The accumulated MCT droplets in the liver could explain the higher liver weight to body weight percentage observed with MCT supplemented rats. Future toxicology and histological studies will be needed to determine the cause of the observed hepatomegaly. It should be emphasized that the dose in this study is not optimized in humans. We speculate that an optimized human dose would be lower and may not cause hepatomegaly or potential fat accumulation. Nutritional ketosis achieved with the KD has been shown to decrease inflammatory markers such as TNF-α, IL-6, IL-8, MCP-1, E-selectin, I-CAM, and PAI-1 [8, 46], which may account for the observed decrease in spleen weight. As previously mentioned, Veech and colleagues demonstrated that exogenous supplementation of 5 mM βHB resulted in a 28 % increase in hydraulic work in the working perfused rat heart and a significant decrease in oxygen consumption [28, 41, 42]. Ketone bodies have been shown to increase cerebral blood flow and perfusion [95]. Also, ketone bodies have been shown to increase ATP synthesis and enhance the efficiency of ATP production [14, 28, 40]. It is possible that sustained ketosis results in enhanced cardiac efficiency and O2 consumption. Even though the size of the heart did not change for any of the ketone supplements, further analysis of tissues harvested from the ketone-supplemented rats will be needed to determine any morphological changes and to understand changes in organ size. It should be noted that the Harlan standard rodent chow 2018 is nutritionally complete and formulated with high-quality ingredients to optimize gestation, lactation, growth, and overall health of the animals. The same cannot be said for the standard American diet (SAD). Therefore, we plan to investigate the effects of ketone supplements administered with the SAD to determine if similar effects will be seen when the micronutrient deficiencies and macronutrient profile mimics what most Americans consume.

Perfect Keto MCT Oil Powder is number one on this list for a few different reasons. The company is founded by functional medicine clinician Dr. Anthony Gustin and each ingredient is used in specific amounts to provide maximum ketone benefits. They use zero binders and fillers often found in other MCT oil powders. It’s a premium product and they don’t make up for it by jacking up the price. However, number 3 on this list has a very similar product at a better value. That’s what keeps this from being a complete 5. However, it’s quality is one of the very best. This MCT Oil powder is one of the only MCT powders that uses ZERO additives and fillers.

Over the past couple years, I’ve tried a number of ketone supplements, generally to enhance a longer fast or to offer an edge before one of my Ultimate Frisbee evenings. This Kegenix variety is one I’d recommend. I’ve also used Quest Nutrition MCT oil powder with good results as well, but there are plenty of other solid formulations to choose from.
This was a big surprise. We were at the very least expecting that drinking a ketone supplement would cause blood ketones to rise, but an average increase of 0.33 mmol/L is very small. The supplement associated with the highest average increase in blood ketones was Prüvit’s Keto-OS Max, but it was only an increase of 0.6 mmol/L. Brianna Stubbs, the ketone researcher I consulted with, agrees that an increase of below 2.0-3.0 mmol/L is unlikely to be of much use.
So if you really want to jump start ketosis, do what the prehistoric humans did; don’t eat for 3 to 5 days. Keep the water bottle and multivitamins close and go on a strict fast. It might seem extreme and to a degree it is, but starving yourself will put you into ketosis. No ifs, ands, or buts about it. And it will cause you to lapse into a ketogenic state faster than if you tried to do so by manipulating the foods you eat (replacing carbs with fats). Once starvation has caused your body to transition to a ketogenic state, you can begin to introduce your low carb, high fat keto-friendly foods.
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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