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If you're healthy and eating a balanced diet, your body controls how much fat it burns, and you don't normally make or use ketones. But when you cut way back on your calories or carbs, your body will switch to ketosis for energy. It can also happen after exercising for a long time and during pregnancy. For people with uncontrolled diabetes, ketosis is a sign of not using enough insulin.

Fascinating stuff and I am quite curious how we know for certain one is actually in ketosis i.e. using ketones as primary fuel source BECAUSE we do know that glucose has a shorter metabolic pathway to burn and under most conditions, given the presence of glucose, that is what the body will default to which is why high fat and high sugar together in diet is so detrimental. So if we use one or more of the above “boosters” and show high levels of blood ketones but also highish levels of glucose (during initial transition) will be mostly burning ketones or still defaulting to glucose?
So in the end, I ordered 1kg of pure BHB Magnesium from a supplier in China and I will be developing my own Ketone product with 30 servings as a lower price than all the competitors, and with more Magnesium, and Calcium in it than Sodium so that it tastes the best and actually helps with weight loss (which Magnesium is proven to do at the right amount). What the companies don’t tell you is that actually Sodium BHB is the cheapest, then Calcium BHB and then Magnesium BHB to source so I would be interested in knowing if what you wrote is actually true or just an excuse to make the product cheaper. Probably a mix of both.

So in the end, I ordered 1kg of pure BHB Magnesium from a supplier in China and I will be developing my own Ketone product with 30 servings as a lower price than all the competitors, and with more Magnesium, and Calcium in it than Sodium so that it tastes the best and actually helps with weight loss (which Magnesium is proven to do at the right amount). What the companies don’t tell you is that actually Sodium BHB is the cheapest, then Calcium BHB and then Magnesium BHB to source so I would be interested in knowing if what you wrote is actually true or just an excuse to make the product cheaper. Probably a mix of both.
I'm at 240 now and actually weigh less than I did in high school. Have a decent amount of excess skin that skews my actual weight. Thankfully the government of Canada pays for plastic surgery in my case because it could lead to health problems in the future. Surgery is in about 8 or so months and I'm quite excited to start a completely new chapter of my life once it's done.
Thanks for all of the great info!! I have Hashimoto’s and would really like to try a high fat/low carb diet. You mentioned that this might not be a good option for people with thyroid issues. How do you recommend I modify my diet to lose weight taking into consideration the Hashimoto’s. I take Westhroid, a non-synthetic thyroid supplement to help with my sluggish thyroid. Thanks so much for any advice you can give me. :)
Hi Ben, great article. I have been a keto-adapted athlete for over 2 years, all through nutrition (65/25/10). I have recently discovered UCAN, KetoOS and MAP Aminos. So, here’s my question: If I am going out for a 4-hour ride, and I want to fuel myself just on these supplements and my body’s natural fat stores, how and in what order should I take them? If I take them all together, will the aminos in the KetoOS interfere with MAP Aminos? Or should I just make a mix of the UCAN and KetoOS in 10oz of water and use it to wash back my 6 MAP tablets, 15-mins before my ride? Thanks for your advice!
Moreover, recent studies show that the Inuit have evolved a number of rare genetic adaptations that make them especially well suited to eat large amounts of omega-3 fat.[57][58][59] And earlier studies showed that the Inuit have a very high frequency—68% to 81% in certain arctic coastal populations—of an extremely rare autosomal recessive mutation of the CPT1A gene—a key regulator of mitochondrial long-chain fatty-acid oxidation[60][61]—which results in a rare metabolic disorder known as carnitine palmitoyltransferase 1A (CPT1A) deficiency and promotes hypoketotic hypoglycemia—low levels of ketones and low blood sugar.[62] The condition presents symptoms of a fatty acid and ketogenesis disorder.[62] However, it appears highly beneficial to the Inuit[60] as it shunts free fatty acids away from liver cells to brown fat, for thermogenesis.[63][64] Thus the mutation may help the Inuit stay warm by preferentially burning fatty acids for heat in brown fat cells.[64] In addition to promoting low ketone levels, this disorder also typically results in hepatic encephalopathy (altered mental state due to improper liver function), enlarged liver and high infant mortality.[65] Inuit have been observed to have enlarged livers with an increased capacity for gluconeogenesis, and have greater capacity for excreting urea to remove ammonia, a toxic byproduct of protein breakdown.[57][66][67][68] Ethnographic texts have documented the Inuit's customary habit of snacking frequently [69] and this may well be a direct consequence of their high prevalence of the CPT1A mutation[70] as fasting, even for several hours, can be deleterious for individuals with that allele, particularly during strenuous exercise.[57][70] The high frequency of the CPT1A mutation in the Inuit therefore suggests that it is an important adaptation to their low carbohydrate diet and their extreme environment.[57][60][70]

I’ll warn you: when you first start using BHB salts like KetoCaNa, it can cause some temporary GI upset until you get acclimated to use. For me, this manifested in just a little bit of gas and bloating that subsided after about one week of use. Additionally, you should know that this product contains salt, so it counts as part of your daily salt intake.
Ben, great article! I recently did my own ketosis experiment and didn’t catch the 100-200g advise until later than I should have, I’m guessing. Great results for 1-2 months but after 3 months I quit sleeping through the night and would wake after about 4 hours of rest each night. My guess is that the extra carbs at night coupled with iodine supplements should allow me to “have my cake and eat it too?” Any other suggestions on the sleep issue? I’ve gone back to High Fat/Low Carb, have improved sleep but I do miss nutritional ketosis and want to try again once my sleep is stable. Thank YOU!!!
Adipose tissue can be used to store fatty acids for regulating temperature and energy.[21] These fatty acids can be released by adipokine signaling of high glucagon and epinephrine levels, which inversely corresponds to low insulin levels. High glucagon and low insulin correspond to times of fasting or to times when blood glucose levels are low.[23] Fatty acids must be metabolized in mitochondria in order to produce energy, but free fatty acids cannot penetrate biological membranes due to their negative electrical charge. So coenzyme A is bound to the fatty acid to produce acyl-CoA, which is able to enter the mitochondria.
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So which MCT to pick? Brain Octane (pure C8) provides the fastest rise in ketones and burns the cleanest, with minimal gut irritation. XCT oil is more affordable but works more slowly with less direct cognitive effects. The capric acid C10 in XCT Oil doesn’t break down into ketones as quickly as pure caprylic C8, but capric acid C10 is more affordable, so you can save money by going with the XCT oil. XCT oil still goes to brain energy, just not as quickly as Brain Octane. Both can be used for energy without processing by the liver, unlike many other fats and oils.
“Muscle loss on the ketogenic diet is an ongoing area of research,” says Edwina Clark, RD, a dietitian in private practice in San Francisco. “Small studies suggest that people on the ketogenic diet lose muscle even when they continue resistance training. This may be related to the fact that protein alone is less effective for muscle building than protein and carbohydrates together after exercise.” Meanwhile, according to a small study published in March 2018 in the journal Sports, people following the keto diet for three months lost about the same amount of body fat and had about the same muscle mass changes as people following normal diets. Yet the folks on keto did lose more leg muscle.
Hi Ben…first, I have learned so much from you, thank you! I’m interested in using exogenous ketone supplements and I have a question for you. I just read the transcript of an interview Dave Asprey did with Dr. Richard Veech (episode 299). He advises against them, and says they can even be harmful. I was disappointed to read this, and wanted to ask you about it, since I respect your opinion greatly….thank you.
The concentration of ketone bodies may vary depending on diet, exercise, degree of metabolic adaptation and genetic factors. Ketosis can be induced when a ketogenic diet is followed for more than 3 days.[34] This induced ketosis is sometimes called nutritional ketosis.[35] This table shows the concentrations typically seen under different conditions[1]

But people who started following the keto diet noticed weight loss for a few reasons: When you eat carbs, your body retains fluid in order to store carbs for energy (you know, in case it needs it). But when you’re not having much in the carb department, you lose this water weight, says Warren. Also, it's easy to go overboard on carbohydrates—but if you're loading up on fat, it may help curb cravings since it keeps you satisfied.
In addition to the seaweed and glycogen carbohydrates mentioned above, the Inuit can access many plant sources. The stomach contents of caribou contain a large quantity of partially digested lichens and plants, which the Inuit once considered a delicacy. They also harvested reindeer moss and other lichens directly. The extended daylight of the arctic summer led to a profusion of plant life, and they harvested plant parts including berries, roots and stems, as well as mushrooms. They preserved some gathered plant life to eat during winter, often by dipping it in seal fat.[71]

In 1921, Rollin Turner Woodyatt reviewed the research on diet and diabetes. He reported that three water-soluble compounds, β-hydroxybutyrate, acetoacetate, and acetone (known collectively as ketone bodies), were produced by the liver in otherwise healthy people when they were starved or if they consumed a very low-carbohydrate, high-fat diet.[10] Dr. Russell Morse Wilder, at the Mayo Clinic, built on this research and coined the term "ketogenic diet" to describe a diet that produced a high level of ketone bodies in the blood (ketonemia) through an excess of fat and lack of carbohydrate. Wilder hoped to obtain the benefits of fasting in a dietary therapy that could be maintained indefinitely. His trial on a few epilepsy patients in 1921 was the first use of the ketogenic diet as a treatment for epilepsy.[10]
Here are a few of the most common side effects that I come across when people first start keto. Frequently the issues relate to dehydration or lack of micronutrients (vitamins) in the body. Make sure that you’re drinking enough water (close to a gallon a day) and eating foods with good sources of micronutrients. To read more on micronutrients, click here >
Great post!! I’m a 41 year old Master CrossFit athlete, been in keto / LCHF Primal lifestyle for the past 9 years. I feel that my performance has improved a lot and continues to improve pretty significantly. I was a top 200 Master Open Qualifier on 2016 and 2017 and I’m usually on the podium of local competitions so my performance is really not bad…and I’m totally fat adapted. I follow sort of a TKD where I sometimes eat carbs at night during the week, but never above 100g so It doesn’t even kick me out of ketosis due to activity level. I’ve been playing with some measurements and I noticed that my BG reading after high intensity training sessions is really high (up to 180mg/dl). But it goes down fast (sometimes it goes down to 50mg/dl but I show no side effect of hypo, function completely normal). From my research, the high glucose post high intensity is normal and due to the stressful response of the exercise and also because my liver is producing the glucose from gluconeogeneses to provide it for the workouts, when needed. This only happens when the workouts are long, above 30 minutes.
Thorne Research has decided to discontinue their Glycofuse product, right when I started using it! Current inventory is expected to run out in June or July. I contacted them to ask if it was being replaced with a new product and at this time they are not able to answer that question, and suggested checking back in with them in June/July. Short of stocking up on a case of it, do you have another recommended product that is as clean & functional as the Glycofuse? This recipe in the blog post above has been working great for me this last month. I’m bummed I’m already going to have to switch it up again!
^ Fumagalli M, Moltke I, Grarup N, Racimo F, Bjerregaard P, Jørgensen ME, Korneliussen TS, Gerbault P, Skotte L, Linneberg A, Christensen C, Brandslund I, Jørgensen T, Huerta-Sánchez E, Schmidt EB, Pedersen O, Hansen T, Albrechtsen A, Nielsen R (September 2015). "Greenlandic Inuit show genetic signatures of diet and climate adaptation". Science. 349 (6254): 1343–7. Bibcode:2015Sci...349.1343F. doi:10.1126/science.aab2319. hdl:10044/1/43212. PMID 26383953.
Adipose tissue can be used to store fatty acids for regulating temperature and energy.[21] These fatty acids can be released by adipokine signaling of high glucagon and epinephrine levels, which inversely corresponds to low insulin levels. High glucagon and low insulin correspond to times of fasting or to times when blood glucose levels are low.[23] Fatty acids must be metabolized in mitochondria in order to produce energy, but free fatty acids cannot penetrate biological membranes due to their negative electrical charge. So coenzyme A is bound to the fatty acid to produce acyl-CoA, which is able to enter the mitochondria.
^ Jump up to: a b c Taboulet P, Deconinck N, Thurel A, Haas L, Manamani J, Porcher R, Schmit C, Fontaine JP, Gautier JF (April 2007). "Correlation between urine ketones (acetoacetate) and capillary blood ketones (3-beta-hydroxybutyrate) in hyperglycaemic patients". Diabetes & Metabolism. 33 (2): 135–9. doi:10.1016/j.diabet.2006.11.006. PMID 17320448.
Keto breath, on the other hand, is less of a side-effect and more of a harmless inconvenience (your breath literally smells like nail polish remover). Basically, when your body breaks down all that extra fat on the keto diet, it produces ketones—one of which is the chemical acetone, Keatley previously told WomensHealthMag.com. (Yes, the same stuff that's in nail polish remover.)
What are the ideal levels of blood sugar? A blood sugar or blood glucose chart identifies ideal levels throughout the day, especially before and after meals. The charts allow doctors to set targets and monitor diabetes treatment, and they help people with diabetes to self-assess. Learn more about guidelines, interpreting results, and monitoring levels here. Read now
It is possible to combine the results of several small studies to produce evidence that is stronger than that available from each study alone—a statistical method known as meta-analysis. One of four such analyses, conducted in 2006, looked at 19 studies on a total of 1,084 patients.[23] It concluded that a third achieved an excellent reduction in seizure frequency and half the patients achieved a good reduction.[18]
Easy: use about half of the recommended serving of Glycofuse, and instead add one scoop of Catalyte electrolytes, one scoop of Kion Aminos, and one serving of ketones and/or MCT’s in the form of Brain Octane, KetoCaNa or KETO//OS (pick your poison, it’s up to you). While any of these forms of ketones and/or MCT’s works for daily focus and short workouts, I found that for long workouts they aren’t very gut friendly unless you really spread out the dosage (e.g. one serving every three hours), so you’d only really use that stuff in something like, say, an Ironman triathlon or multi-day adventure race.
If you have high triglycerides and low HDL, or you have any type of genetic issue that would cause you to have high sensitivity to saturated fats then the diet may not actually be for you. I think you should start by reading this: https://bengreenfieldfitness.com/article/nutritio… If you prefer a more direct, customized approach, I'd be happy to help you via a personal one-on-one consult. Just go to https://bengreenfieldfitness.com/coaching and then choose a 20 or 60-minute consult, whichever you'd prefer. I can schedule ASAP after you get that.
In the first week, many people report headaches, mental fogginess, dizziness, and aggravation. Most of the time, this is the result of your electrolytes being flushed out, as ketosis has a diuretic effect. Make sure you drink plenty of water and keep your sodium intake up.6One of the fathers of keto, Dr. Phinney, shows that electrolyte levels (especially sodium) can become unbalanced with low carb intake.
Keto, or Ketogenic diets, limit the amount of carbohydrates you eat and increase the amount of fat you eat in order to get your metabolism into a state of Ketosis. In Ketosis, your body burns fat for fuel instead of carbohydrates (it’s preferred fuel). The Ketogenic diet is known as a way to lose weight because as you provide less carbohydrates, your body will burn the fat you eat and have stored as fuel. But Ketogenic diets are also known for their multiple health benefits. To read more, check out our blog post on Ketogenic diets here.

Great post!! I’m a 41 year old Master CrossFit athlete, been in keto / LCHF Primal lifestyle for the past 9 years. I feel that my performance has improved a lot and continues to improve pretty significantly. I was a top 200 Master Open Qualifier on 2016 and 2017 and I’m usually on the podium of local competitions so my performance is really not bad…and I’m totally fat adapted. I follow sort of a TKD where I sometimes eat carbs at night during the week, but never above 100g so It doesn’t even kick me out of ketosis due to activity level. I’ve been playing with some measurements and I noticed that my BG reading after high intensity training sessions is really high (up to 180mg/dl). But it goes down fast (sometimes it goes down to 50mg/dl but I show no side effect of hypo, function completely normal). From my research, the high glucose post high intensity is normal and due to the stressful response of the exercise and also because my liver is producing the glucose from gluconeogeneses to provide it for the workouts, when needed. This only happens when the workouts are long, above 30 minutes.


A high-fat diet also trains your body to burn even more fat during exercise, even at high intensities. Fat is released faster and in greater amounts from your storage adipose tissue and transported more quickly into your muscles and mitochondria. Your muscles also store more energy as fat and use this fat-based fuel more efficiently and quickly. Even more interestingly, a high-fat diet can cause a shift in the gene expression that codes for specific proteins that increase fat metabolism – and create very similar adaptations to exercise itself. So the mere act of shifting primary fuel intake from carbohydrates to fat begins to make you more “fit”, even if you’re not exercising.
The classic ketogenic diet is not a balanced diet and only contains tiny portions of fresh fruit and vegetables, fortified cereals, and calcium-rich foods. In particular, the B vitamins, calcium, and vitamin D must be artificially supplemented. This is achieved by taking two sugar-free supplements designed for the patient's age: a multivitamin with minerals and calcium with vitamin D.[18] A typical day of food for a child on a 4:1 ratio, 1,500 kcal (6,300 kJ) ketogenic diet comprises three small meals and three small snacks:[28]

The difference between ketosis and ketoacidosis is the level of ketones in the blood. Ketosis is a physiological adaptation to a low carbohydrate environment like fasting or a ketogenic diet. There are situations (such as treatment-resistant epilepsy) where ketosis can be beneficial to health. Ketoacidosis is an acute life-threatening state requiring prompt medical intervention; its most common form is diabetic ketoacidosis where both glucose and ketone levels are significantly elevated.
The ketone bodies are possibly anticonvulsant; in animal models, acetoacetate and acetone protect against seizures. The ketogenic diet results in adaptive changes to brain energy metabolism that increase the energy reserves; ketone bodies are a more efficient fuel than glucose, and the number of mitochondria is increased. This may help the neurons to remain stable in the face of increased energy demand during a seizure, and may confer a neuroprotective effect.[56]

C8 is the rarest MCT found in coconut oil, comprising about 6% of coconut oil. It has potent anti-microbial properties (way more potent than lauric acid) to help you maintain a healthy gut, and it is the fastest MCT to metabolize in the brain. (hence the name Brain Octane). Your liver does not need to process C8, and it only takes the steps for your body to turn it into ATP cellular energy (sugar takes 26 steps). You would need 18 tablespoons of coconut oil to get just one tablespoon of Brain Octane.

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