As seen in this exercise, glucose tends to fall quite precipitously following exogenous ketone ingestions. Without exception, every time I ingested these compounds (which I’ve probably done a total of 25 to 30 times), my glucose would fall, sometimes as low as 3 mM (just below 60 mg/dL). Despite this, I never felt symptomatic from hypoglycemia. Richard Veech (NIH) one of the pioneers of exogenous ketones, has suggested this phenomenon is the result of the ketones activating pyruvate dehydogenase (PDH), which enhances insulin-mediated glucose uptake. (At some point I will also write a post on Alzheimer’s disease, which almost always involves sluggish PDH activity —in animal models acute bolus of insulin transiently improves symptoms and administration of exogenous ketones does the same, even without glucose.)
77. Volek JS, Sharman MJ, Gomez AL, Scheett TP, Kraemer WJ. An isoenergetic very low carbohydrate diet improves serum HDL cholesterol and triacylglycerol concentrations, the total cholesterol to HDL cholesterol ratio and postprandial pipemic responses compared with a low fat diet in normal weight, normolipidemic women. J Nutr. 2003;133(9):2756–61. [PubMed]
Keep these studies in mind as your body tries to play tricks on you during your first day of fasting.  Even after three days of fasting, health complications are highly unlikely. However, it is important to know about the possible issues that can be caused by fasting. If you choose to incorporate fasting into your daily diet, you typically want to eat every day as well. Occasionally going on a longer period of fasting.
Methods and Results: In the first study, 15 participants consumed KE or KS drinks that delivered ~12 or ~24 g of βHB. Both drinks elevated blood D-βHB concentrations (D-βHB Cmax: KE 2.8 mM, KS 1.0 mM, P < 0.001), which returned to baseline within 3–4 h. KS drinks were found to contain 50% of the L-βHB isoform, which remained elevated in blood for over 8 h, but was not detectable after 24 h. Urinary excretion of both D-βHB and L-βHB was <1.5% of the total βHB ingested and was in proportion to the blood AUC. D-βHB, but not L-βHB, was slowly converted to breath acetone. The KE drink decreased blood pH by 0.10 and the KS drink increased urinary pH from 5.7 to 8.5. In the second study, the effect of a meal before a KE drink on blood D-βHB concentrations was determined in 16 participants. Food lowered blood D-βHB Cmax by 33% (Fed 2.2 mM, Fasted 3.3 mM, P < 0.001), but did not alter acetoacetate or breath acetone concentrations. All ketone drinks lowered blood glucose, free fatty acid and triglyceride concentrations, and had similar effects on blood electrolytes, which remained normal. In the final study, participants were given KE over 9 h as three drinks (n = 12) or a continuous nasogastric infusion (n = 4) to maintain blood D-βHB concentrations greater than 1 mM. Both drinks and infusions gave identical D-βHB AUC of 1.3–1.4 moles.min.
Dusty you assume only everyone wants fat burning. I think this is silly. The brain and heart will prefer ketones over carbohydrates when both are present in the blood stream. Look at the research and mechanism. I don’t want fat loss, I want better brain function. I also regularly eat carbs myself. This is one of the reasons I myself use exogenous ketones. No this isn’t a magic fat loss powder, but don’t sit here and quote T-nation trying to rebuttal this article acting like that is a credible source.
Full disclosure: after carrying out the background research, I was already, as you might imagine, feeling a little less neutral about these products. You may have noticed a hint of that in part 1 of the 2-part video series we made about the project (watch part 2 at the top of this page!). However, and although this was by no means a controlled scientific study under laboratory conditions, we designed the experiment in a very objective way. The aim was to give the supplements the best possible chance of showing the benefits they are claimed to have.
There’s debate raging about which dietary tactic is the god particle for making you leaner, faster and healthier. How the ketogenic diet option squares off against the low carb route is vital for understanding the ways in which exogenous ketone supplements work. To get into ketosis the natural way, you need to keep your carb intake low enough for long enough for your body to begin using use fat as fuel. Your liver then converts a portion of that fat into energy molecules called ketones. These work together with glucose as a fuel source, but can actually kick in faster, allowing your body to operate more economically during lengthy, high-energy exercise efforts.
Blood glucose concentrations are decreased during both exogenous and endogenous ketosis, although by different mechanisms. During endogenous ketosis, dietary carbohydrate deficit is the underlying cause of low blood glucose, along with reduced hepatic gluconeogenesis and increased ketone production (Cahill et al., 1966). With exogenous ketosis, carbohydrate stores are plentiful, yet ketones appear to lower blood glucose through limiting hepatic gluconeogenesis and increasing peripheral glucose uptake (Mikkelsen et al., 2015). One clinical use of the ketogenic diet is to improve blood glucose control, yet the elevated blood FFA may increase the risk of heart failure (Holloway et al., 2009). Thus, the ability of exogenous ketones to lower blood glucose without elevating blood FFA concentrations could deliver the desired effect of the diet, whilst also decreasing a potential risk.

I have, though, recently been diagnosed with ovarian cancer. After reading through your blog, I noticed there was a little about Ketogenetic diet and cancer. I purchased the MCT oil powder in hopes that will help me get into ketosis for the purpose of “starving” the cancer cells. Other then focus, I didn’t see any particular format for something like this. Here are my questions: How much of the powder should I take? And do you think the diet plus the MCT oil is a good idea for 1) aiding chemotherapy and 2) helping shrink the number of cancer cells?
We are told by our parents, doctors, and the media that milk builds strong bones and that we should take calcium supplements to help protect against osteoporosis. Indeed, calcium deficiency can lead to a plethora of health problems[12]. However, those of us who take calcium supplements or consume calcium-fortified foods and beverages may, in fact, be consuming above the Recommended Dietary Allowance (RDA) of calcium.

There is one viable explanation for consuming ketones. If you're in a calorie or carb-restricted state, then maybe during a workout it would make sense. But even then, that really only applies to endurance activities, since it has more to do with enhancing aerobic performance (where oxygen is required), than it does with enhancing high-intensity efforts (where it's not).

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Follow our simple tips to get into ketosis and speed up the process. Our tips are scientifically-proven to work and are completely safe for everyone. If you need more guidance to achieve ketosis safely and effectively, enroll in our free Ketocademy course. The course will teach you everything there is to know about entering ketosis in less than 3 hours. Try it out today!
First and foremost, one of the most important factors is to be discipline when following the ketogenic diet. This means heavily restricting your carbohydrate intake, while switching to high-fat foods and moderate proteins. The general rule of thumb when it comes to splitting your macros out should look something like this: 5% (carbs)/ 80% (fats)/ 15% (proteins). Although if you’re just starting out, I wouldn’t focus too heavily on macros but rather place more importance in restricting your carbohydrate intake to 20 grams or less. Depending on the individual, most keto diets will allow approximately 20g-70g of net carbs as part of your overall daily intake, but if you’re asking the extreme question of ‘how to get into ketosis in 24 hours?’ then let’s focus on the absolute limit. For a more detailed breakdown, please see my keto shopping list article.
77. Volek JS, Sharman MJ, Gomez AL, Scheett TP, Kraemer WJ. An isoenergetic very low carbohydrate diet improves serum HDL cholesterol and triacylglycerol concentrations, the total cholesterol to HDL cholesterol ratio and postprandial pipemic responses compared with a low fat diet in normal weight, normolipidemic women. J Nutr. 2003;133(9):2756–61. [PubMed]
BHB supplementation can drastically enhance your insulin sensitivity, resulting in better shuttling of blood glucose into cells.[10] With type-2 diabetes and insulin resistance becoming growing concerns, BHB supplementation may provide a promising alternative for healthy blood glucose regulation in the coming years.Even for everyday gym goers and fitness enthusiasts, increasing insulin sensitivity via BHB supplementation can be a great benefit as this puts your body in a better position for partitioning nutrients/carbohydrates to energetically demanding, glycolytic tissues, such as skeletal muscle.
Ketones are also a cleaner-burning fuel than carbs. They’re burned for energy in the mitochondria, and fewer free radicals (a highly-reactive, short-lived uncharged molecule) are generated when compared to burning glucose.15 What’s more, ketone molecules themselves cause a decrease in production of free radicals,21,22 while also increasing glutathione–a powerful antioxidant protecting against mitochondrial damage induced by free radicals.23
Patrick Arnold is an organic chemist who is notorious for being the creator of several performance-enhancing steroids. He is arguably one of the strongest influencers on the advancement of sports supplementation. Currently he is focused on developing products under the KetoSports brand, which includes two exogenous ketone products – KetoForce and KetoCaNa.
If Prüvit’s Keto OS-Max is “not a weight loss supplement” as stated in their disclaimer, why is the official website full of success stories of people who claim to have lost huge amounts of weight from taking the supplements? Ketōnd also feature a number of weight loss success stories on their site. I will get to why there is a problem with weight loss claims later on.
In Study 2 a Student's unequal variance t-test with equal SD was used to compare urine βHB concentrations. Additionally, a linear mixed effects model was constructed to estimate partitions of variance in R, using the lme4 and blme packages (Chung et al., 2013; Bates et al., 2015). Feeding state and visit number were fixed effects in this model, and inter-participant variability was a random effect. Inter-participant variability was calculated according to the adjusted generalized R2 metric (as proposed by Nakagawa and Schielzeth, 2013), to partition variance between the fixed effects of feeding, inter-participant variability, and residual variability. The coefficient of variation for βHB Cmax and AUC were calculated using the method of Vangel (1996).
Ketone supplements contain exogenous ketones—synthetic ketones made in a lab. Most use a type of ketone called beta-hydroxybutyrate (BHB), which is the same as the ketones the body produces naturally. “We’re literally biohacking," says Amie Heverly, who began taking a ketone supplement called Prüvit last year and now works as a promoter selling Prüvit products. "You’re not adding a foreign substance to your body, because BHB is identical to what your body would naturally produce,” she explains.
Recently, two published studies investigated the effects of ketone salts in athletes (total n = 22).8,9 Performance over a four-minute cycling time-trial and a 150 kJ ( ~11 mins) cycling time trial were compared between ketone salts vs. carbohydrate. In the four-minute trial there was no change in performance, and in the 150 kJ test, performance decreased by 7%. Blood BHB levels peaked at 0.6 and 0.8 mM in these studies.
I had the chance to interview Dr. Ryan Lowery, Ph.D. about this in person. He performs some (not peer-reviewed) research on different brands of ketone salts and is listed as one of the “specialists” on Prüvit’s website. He suggested that we had perhaps ran the tests too long after the supplements were taken, stating that blood ketones tend to peak at 30 minutes. This is, however, not what Prüvit themselves state in their article on the 59-minute test, or the promise to reach ketosis in 60 minutes on the Kegenix Prime packaging. Plus, do you really want to spend up to $390/month on a product that gives you the benefits of ketosis for half an hour?
Usually, you’ll find exogenous ketones in the form of powdered ketone salts. Less common are ketone esters, which are the purest form of ketones. Griffin says they work quickly (in 10 to 15 minutes, as opposed to an hour for the salts) and effectively, but they’re more expensive, have a more-revolting taste, and are harder to find (HVMN is one U.S. company that sells them). People also use medium-chain triglyceride (MCT) oil — or partially manmade fats — to put the body into a state of ketosis.
The CNS cannot use fat as an energy source; hence, it normally utilizes glucose. After 3–4 days without carbohydrate consumption the CNS is ‘forced' to find alternative energy sources, and as demonstrated by the classic experiments of Cahill and colleagues4 this alternative energy source is derived from the overproduction of acetyl coenzyme A (CoA). This condition seen in prolonged fasting, type 1 diabetes and high-fat/low-carbohydrate diets leads to the production of higher-than-normal levels of so-called ketone bodies (KBs), that is, acetoacetate, β-hydroxybutyric acid and acetone—a process called ketogenesis and which occurs principally in the mitochondrial matrix in the liver.6
One thing to remember here is that even if your calculated daily ‘keto approved’ protein allowance is (let’s say) 150g, that doesn’t mean you can eat 150g in one meal and still be in ketosis. You may find that you can’t eat more than 40g of protein at a time, otherwise you will drop out of ketosis. OR, you may find you can eat 50g of protein but you need a LOT of fat. Whereas a small serve of 15g of protein without fat might knock you out of ketosis. 
In general, too much caffeine on a regular basis can prevent you from going into ketosis. But since we are trying to get into ketosis in 24 hours I believe it will help you for one day by curbing your hunger and getting through the fast easier. In case, you do not like coffee, you can opt for caffeine drinks or you can opt for other beverages which consist of caffeine in smaller quantities.

I don’t think we even need a drumroll here… Based on my background research into ketone-supplement companies, the survey of Diet Doctor users and the experiment itself, we cannot recommend taking these supplements. I can personally think of many more beneficial ways to invest money in my health, such as buying grass-fed meat and organic vegetables, or even buying a bicycle and riding it outside in the sunshine.

The culprit is often restaurant meals or other meals where the nutrition facts are not available with the food itself. Such “ignorance is bliss” situations allow us to avoid dealing with daunting numbers. Many people don’t hesitate to stop and enjoy a meal at a restaurant, but they freak out when they actually see the numbers on a label.  By now, we all know that opting for fatty meat with a side of veggies cooked in butter isn’t that bad after all.  It turns out that what you thought to be the safe, “healthy,” doctor-approved choice might not always be what you think it is.
When the results for the supplement and the placebo were within 0.2 (either % or mmol/L) of each other, we classed the supplement as neither “better” nor “worse” than the placebo. We gave a “winning brand” sticker to the brand that scored highest against the placebo for each marker, but not for physical performance, since none of the supplements performed better than the placebo for that marker.

The two compounds commonly referred to as ‘ketone bodies’ (BOHB and AcAc) are produced and used for multiple purposes across nature from algae to mammals, but seldom in concentrations useful for extraction as human food. For this reason, the source of most exogenous ketones is chemical synthesis. Furthermore, most current research and use of ketone supplements focuses on BOHB. That is because AcAc is chemically unstable – it slowly breaks down to form acetone by releasing of one molecule of CO2.
Exogenous ketones cause the body to rely less on fat as fuel (see Fig 3). Fat takes longer to metabolise for energy than muscle glycogen. This is why fatty acids are not the preferred fuel under heavy exercise. This could be useful for keto-adapted athletes performing high-intensity cardiovascular or strength training.12 This is particularly useful for the Keto-adapted athlete who wants to undergo high-intensity cardiovascular or strength training.
The ‘carb-sparing’ effect from BHB suppresses the break down of muscle glycogen. This leads to lower lactate levels. When increasing exercise intensity, fat oxidation (burning) reaches a limit. At that point the muscle burns carbohydrates as fuel. But when consuming Ketone esters, the body does not make this switch. This suggests Ketones are being used instead. 11
Besides cutting carbs, it's important to increase your fat intake, and be moderate with protein. The fat you eat will keep you feeling energized and support ketone production. Protein is also important but if you go overboard with it, your body could enter into a process called gluconeogenesis. In gluconeogenesis, your body makes glucose from protein, and you want to avoid that.
There are several ways to approach the “intermittent” part of food restriction. One of the most common is limiting the window in which food is consumed to about eight hours a day. Another is fasting for a full 24 hours once a week, or once a month. Fasting beyond three days can be stressful on the body and should be done with medical advice and supervision.
Some general side effects of your body producing beta hydroxybutyrate is essentially the lull in time it takes to switch from carbohydrate metabolism to fat metabolism, which can take 3-4 days. This can lead to mood swings, fatigue, and general low energy. If you want to skip that step, we recommend taking exogenous BHBs to switch your body over effortlessly.
Blood, urine, plasma, and breath ketone concentrations following mole-matched ketone ester or isocaloric dextrose drinks in fed and fasted subjects (n = 16) at rest. Data from both of the two study visits in each condition (fed and fasted) completed by an individual are included in the analysis. Values are means ± SEM. (A) Blood d-βHB. (B) AUC of blood d-βHB. (C) Urine d-βHB excretion. (D) Plasma acetoacetate (AcAc). (E) Measured breath acetone (ppm = parts per million). (F,G) Mean d-βHB Cmax and difference between βHB Cmax over two visits when subjects separately consumed two ketone ester drinks in both the fed (F) and fasted (G) state. X axis = mean d-βHB Cmax of the 2 visits (mM), Y axis = difference between d-βHB Cmax in each visit. 95% confidence limits are shown as dotted lines. Significance denoted by: *p < 0.05 fed vs. fasted.

However, it's important to NEVER overlook the power of exercise and of course sticking to a proper routine to get the most optimized results. The most common mistake people make is by treating any keto supplement like a "wonder drug" that will help them shed weight in their sleep. Seriously... how is that even scientifically possible. So if you are thinking about trying out a particular keto supplement, I would suggest two things:
Long-Term Effects of a Ketogenic Diet in Obese Patients – The present study shows the beneficial effects of a long-term ketogenic diet. It significantly reduced the body weight and body mass index of the patients. Furthermore, it decreased the level of triglycerides, LDL cholesterol and blood glucose, and increased the level of HDL cholesterol. Administering a ketogenic diet for a relatively longer period of time did not produce any significant side effects in the patients. Therefore, the present study confirms that it is safe to use a ketogenic diet for a longer period of time than previously demonstrated.

When your body is done using up a certain substrate to create energy (acetyl-CoA) after eating carbohydrates, it will start to find creative ways to get the job done. This is something that you want to happen. This is the switch to ketosis. If you didn’t do this, you’d be dead after fasting for a very short period of time. Under normal circumstances, the liver will start making beta-hydroxybutyrate from long chain and medium chain fatty acids that are liberated from your fat tissue. You are turning fat into fuel. Good work. This is why people can fast for months at a time and still function like normal humans.
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!
Because they’re so expensive, you want to make sure you pick a good one. Griffin and Langer say to ignore the companies that make these supplements sound too good to be true. Just like with any supplement, Griffin says it’s important to look at what’s in it. Beware of products with lots of fillers and instead go for one with a short, straightforward list of ingredients (Griffin likes the options from KetoSports).
Ketone Bodies are then used by tissues as a source of energy3 through a pathway that leads to formation from β-hydroxybutyrate of two molecules of acetyl CoA, which are used finally in the Krebs cycle. It is interesting to note that the KBs are able to produce more energy compared with glucose because of the metabolic effects of ketosis—the high chemical potential of 3-β-hydroxybutyrate leads to an increase in the ΔG0 of ATP hydrolysis.3 
 Effects of beta-hydroxybutyrate on cognition in memory-impaired adults. – Glucose is the brain’s principal energy substrate. In Alzheimer’s disease (AD), there appears to be a pathological decrease in the brain’s ability to use glucose. Neurobiological evidence suggests that ketone bodies are an effective alternative energy substrate for the brain. Elevation of plasma ketone body levels through an oral dose of medium chain triglycerides (MCTs) may improve cognitive functioning in older adults with memory disorders. On separate days, 20 subjects with AD or mild cognitive impairment consumed a drink containing emulsified MCTs or placebo. Significant increases in levels of the ketone body beta-hydroxybutyrate (beta-OHB) were observed 90 min after treatment (P=0.007) when cognitive tests were administered. beta-OHB elevations were moderated by apolipoprotein E (APOE) genotype (P=0.036). For 4+ subjects, beta-OHB levels continued to rise between the 90 and 120 min blood draws in the treatment condition, while the beta-OHB levels of 4- subjects held constant (P<0.009). On cognitive testing, MCT treatment facilitated performance on the Alzheimer’s Disease Assessment Scale-Cognitive Subscale (ADAS-cog) for 4- subjects, but not for 4+ subjects (P=0.04). Higher ketone values were associated with greater improvement in paragraph recall with MCT treatment relative to placebo across all subjects (P=0.02). Additional research is warranted to determine the therapeutic benefits of MCTs for patients with AD and how APOE-4 status may mediate beta-OHB efficacy.
Ketostix are very unreliable. There are many factors which can alter results such as hydration level, if you’ve worked out recently and the amount of unused ketones in your body to name just a few. Never rely of Ketostix to determine whether you are in ketosis or not. The Precision Xtra blood ketone monitor is the gold standard for testing for ketones in your body. After following a ketogenic diet for a while, you should be able to tell if you are in ketosis or not by the way you feel.
I wrote this post at about the same time Germany won the World Cup in Rio de Janeiro in 2014. There’s been a lot of moving and shaking in the world of exogenous ketones since then, not to mention soccer. Looking back on my post, I still consider it relevant in terms of what exogenous ketones possibly can (and cannot) do for performance. In this case, to see if exogenous ketone esters provide me a “boost” by allowing me to do the same amount of work while expending less energy (and work at a relatively lower VO2) compared to no supplementation.

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