^ 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.

Hi Ben – Great article. I had trouble at the end figuring out if you were now eating high fat (60-80% of calories), or if you went back to something closer to 50% fat calories and higher carbs and are using exogenous ketones to get int ketosis when needed. Are you doing any carbs at night or a refeed, or just having higher carbs on most days? Thanks

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.


After 2 years in ketosis suddenly I find my blood glucose has risen to high levels even while in ketosis. I thought it was the dawn phenomenon, stress hormones like cortisol but now I am beginning to think I am eating too many exongenous keytones like too much MCT oil? I am not taking exogenous keytone supplements but wondering if too much oil/ fat in the diet generates exogenous keytones which inhibits the livers production of endogenous keytones. I have read if the liver is producing endogenous keytones it is not at the same time producing glucose through gluconeogenisis?
C12 is about 50+% of coconut oil, and it requires a pit stop in the liver rather than getting immediately converted into energy like the other MCT’s listed above. This is why it is more accurately described as an LCT, not an MCT like marketers claim. It raises cholesterol more than any other fatty acid. It is also commonly cited as having antimicrobial benefits, which is does – except the shorter chain MCT oils are more effective against candida yeast infections, and even gonorrhea and chlamydia.
^ Jump up to: a b c d e f g h i j k l m n o p q r s Kossoff EH, Zupec-Kania BA, Amark PE, Ballaban-Gil KR, Bergqvist AG, Blackford R, et al. Optimal clinical management of children receiving the ketogenic diet: recommendations of the International Ketogenic Diet Study Group. Epilepsia. 2009 Feb;50(2):304–17. doi:10.1111/j.1528-1167.2008.01765.x. PMID 18823325
3) Cholesterol levels usually go up with inflammation, because inflammation causes damage to the tissues, and cholesterol is manufactured and released in circulation to patch things up. So, again, eating high fat is the best way to drop inflammation; not increase it. My hsCRP are always below 0.1, and most of the time, below detection level. Oxidation of cholesterol causes inflammation; not the other way around. So, your point about inflammation is a non-issue.
When you eat foods high in carbohydrates and fat, your body naturally produces glucose. Carbohydrates are the easiest thing for the body to process, and therefore it will use them first – resulting in the excess fats to be stored immediately. In turn, this causes weight gain and health problems that are associated with high fat, high carbohydrate diets (NOT keto).

Apparently, Dominic’s research seems to be suggesting the fact that diet-induced ketosis from a high-fat, low-carb intake, especially when combined with the use of nutrition supplements such as powdered ketones or MCT oil, can vastly reduce the need for the brain to use oxygen to burn glucose. This is because the brain can use up to around 75% of its fuel from ketones. So a ketone-fed or a fat-adapted brain can be better equipped to withstand low oxygen availability and potentially support longer breath-hold times. Dominic’s research also shows that in the presence of ketosis, the brain and body are able to resist the potential cell damage of long periods of time with low oxygen, also known as “hypoperfusion”.


As a matter of fact, it’s more dangerous to have high levels of cholesterol and high levels of CRP than low levels of cholesterol and high levels of CRP – even if your high levels of cholesterol are “healthy”, big fluffy LDL particles, and not small, dense vLDL particles. In other words, no matter how many healthy fats you’re eating, these fats may actually come back to bite you if you’re creating high inflammation from too much exercise, not enough sleep, exposure to toxins and pollutants, or a high-stress lifestyle.

“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.

In fact, most folks have enough stored body fat to fuel aerobic activity for days and days without running out of energy. For example, a 150 pound dude at a hot, sexy and ripped at 8% body fat still carries 12 pounds of storage fat – which at 3500 calories per pound of fat can easily liberate 42,000 calories of useable fuel for exercise. You’ve got those same thousands of calories sitting around your waist, abs, hip, butt and thighs – just sitting there, waiting to be burnt.


Once inside the mitochondrion, the dominant way that the bound fatty acids are used as fuel in cells is through β-oxidation, which cleaves two carbons off of the acyl-CoA molecule in every cycle to form acetyl-CoA.[24] Acetyl-CoA enters the citric acid cycle, where it undergoes an aldol condensation with oxaloacetate to form citric acid; citric acid then enters the tricarboxylic acid cycle (TCA), which harvests a very high energy yield per carbon in the original fatty acid.[25][26]
You’re transitioning. Your body is equipped to process a high intake of carbs and a lower intake of fat. Your body needs to create enzymes to be able to do this. In the transitional period, the brain may run low on energy which can lead to grogginess, nausea, and headaches. If you’re having a large problem with this, you can choose to reduce carb intake gradually. 

Yes, they're technically a fruit, but we think olives deserve a shout-out all of their own, since they're also a great source of healthy fats and are one of a few keto-approved packaged foods. Plus, they're a great source of antioxidants, will satisfy your craving for something salty, and are blissfully low-carb. “About a palm's worth only has 3 grams of net carbs,” Sarah Jadin, RD, told Health in a previous interview.
The first cellular fuel is glucose, which is commonly known as blood sugar. Glucose is a product of the starches and sugars (carbohydrates) and protein in our diet. This fuel system is necessary, but it has a limitation.  The human body can only store about 1000-1600 calories of glucose in the form of glycogen in our muscles and liver. The amounts stored depend on how much muscle mass is available.  Men will be able to store more because they have a greater muscle mass.  Since most people use up about 2000 calories a day just being and doing normal stuff, you can see that if the human body depended on only sugar to fuel itself, and food weren’t available for more than a day, the body would run out of energy. Not good for continuing life.
After increasing water intake and replacing electrolytes, it should relieve most all symptoms of Keto Flu. For an average person that is starting a ketogenic diet, eating 20-30g of net carbs a day, the entire adaptation process will take about 4-5 days. My advice is to cut your carbs to fewer than 15g to ensure that you are well on your way into ketosis within one week. If you are experiencing any more keto flu symptoms, double check your electrolyte intake and adjust.

I just discovered your site and have been thoroughly enjoying many of the articles and appreciate that you get so in depth in your explanations. I’m in my late 40’s and, while not an extreme endurance athlete, I am moderately active with 18-20 mile rides 3x a week as well as some boxing and body weight resistance (push up, pull up, etc) mixed in. I’ve generally been paleo and stick to quality macros for the most part (grass fed meats/dairy, organic veg and oils) and zero supplements. I recently started following keto (after reading this article) about 10 days ago and things seem good thus far. I do, however, want to avoid any of the negative side effects you mention and also not lose any lean muscle. I’m currently about 174 lbs, 5’8″ and about 19% bodyfat – I’m taking in about 95g protein, 130g fat and <20g net carbs. I'm eating all quality – wild salmon, grass fed beef, pastured eggs, coconut oil, Brain Octane and Grass fed butter in coffee, sardines, etc. With a smattering of organic veg, but it seems real easy to bust through the carb barrier. *I'M ALSO TAKING KETOCANA PRE-WORKOUT* and I notice this is keeping me going throughout a ride or the gym.

Being in optimal ketosis for a prolonged period of time (say, a month) will ensure that you experience the maximal hormonal effect from eating a low-carb diet. If this doesn’t result in noticeable weight loss, you can be certain that too many carbs are NOT part of your weight issue and not the obstacle to your weight loss. There are, in fact, other causes of obesity and being overweight. The next three tips in this series might help you. 

After initiation, the child regularly visits the hospital outpatient clinic where they are seen by the dietitian and neurologist, and various tests and examinations are performed. These are held every three months for the first year and then every six months thereafter. Infants under one year old are seen more frequently, with the initial visit held after just two to four weeks.[9] A period of minor adjustments is necessary to ensure consistent ketosis is maintained and to better adapt the meal plans to the patient. This fine-tuning is typically done over the telephone with the hospital dietitian[19] and includes changing the number of calories, altering the ketogenic ratio, or adding some MCT or coconut oils to a classic diet.[18] Urinary ketone levels are checked daily to detect whether ketosis has been achieved and to confirm that the patient is following the diet, though the level of ketones does not correlate with an anticonvulsant effect.[19] This is performed using ketone test strips containing nitroprusside, which change colour from buff-pink to maroon in the presence of acetoacetate (one of the three ketone bodies).[45]
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“To achieve the relatively high rates of intake (up to 90 grams/hour) needed to optimize results in events lasting longer than three hours, athletes should practice consuming carbohydrates during training to develop an individual strategy, and should make use of sport foods and drinks containing carbohydrate combinations that will maximize absorption from the gut and minimize gastrointestinal disturbances.”
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“Rapid, significant weight loss is a common side effect of the keto diet because of the water losses that occur as carbohydrate stores are depleted,” says Clark. In a study in the American Journal of Clinical Nutrition, obese men following a modified version of the ketogenic diet, with high protein and low carbs, lost about 14 pounds in one month, compared with the control group, which lost about 10 pounds on a high-protein, medium-carb diet.


Sensational article. I am experimenting with a low carb diet, high fats and moderate protein. I am not keeping strict notes on what I eat but I cut out almost all fruit and I eat eggs, spinach, kale, chard, avacados, hard cheese, walnuts (raw organic) and grass fed meet and butter. I take about 25-30ml of Brain Octane straight a day. I take your probiotic and colostrum (I need to get more regular) and I consume bone broth four days a week. I am looking to live longer and be healthier during that long life. In the short term I want to be smarter and be able to handle stress better. I would also love to avoid cancer and drop a deuce every day. My question is: Is there a point of carb consumption where even combining it with exogenous ketones using your recommendations it would be less effective or cause negative outcomes? Could one consume all the cards and sugar one wanted and use the supplements and still be getting into ketosis and reaping the benefits?
“Studies have shown that the ability to stick to a diet is more important for long-term success than the type of diet that’s followed,” says Yawitz. “Keto is incredibly restrictive and is particularly tough for those who have frequent social engagements or are prone to carb cravings.” The Mediterranean diet allows you to eat carbs, like as many fruits and veggies as you want, along with whole grains. Not to mention, the Mediterranean diet has been linked to a number of other health benefits, including a lower risk of Alzheimer’s and Parkinson’s disease, certain types of cancer, and heart disease, according to the Mayo Clinic.
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A small Feb. 20, 2017, study looked at the impact of a six-week ketogenic diet on physical fitness and body composition in 42 healthy adults. The study, published in the journal Nutrition & Metabolism, found a mildly negative impact on physical performance in terms of endurance capacity, peak power and faster exhaustion. Overall, researchers concluded, “Our findings lead us to assume that a [ketogenic diet] does not impact physical fitness in a clinically relevant manner that would impair activities of daily living and aerobic training.” The “significant” weight loss of about 4.4 pounds, on average, did not affect muscle mass or function.
These are the widely recognized LCT’s, or long chain fatty acids in coconut oil, mostly saturated, including stearic acid (C18:0), oleic acid (C18:1), and linoleic acid (18:2). The exact percentage of each depends on region the coconut is grown, time of harvest, and other growing variables. They are good as a fuel source in your food, and have some of the tastiness of coconut oil, if your goal is getting into ketosis fast, you won’t benefit from eating a lot more of them compared to eating true medium chain fatty acids.
And what I’m writing has nothing to do with taking supplements to induce ketosis or whatever. I believe these things are covered in Volek & Phoney’s book The Art and Science of Low Carb Living, which I would have thought you to be very familiar with. The iodine stuff you can read about in Iodine, Why We Need, Why We Can’t Live Without It by Brownstein.

Amazing article – gonna have to print it and read it again. To much to break down in one sitting. Thanks Ben – you’ve pulled together so much insight and references that’s given me greater confidence and conviction. I’m 50 and use to be super active and a seasoned athlete but after a few ‘mid life surgical interventions’ I had to find a better way… Ketogenics has been that for me… no more inflammation… I can’t tell you how great it’s been to be pain free! Keep leading from the front.


Nutritional ketosis is a natural metabolic state in which your body adapts to burning fat rather than carbohydrates as its primary fuel. It is clinically proven to directly reduce blood sugar (as measured by HbA1c), improve insulin sensitivity (as measured by HOMA-IR) and reduce inflammation (as measured by white blood cell count and CRP). Nutritional ketosis can be induced by following a ketogenic diet. Learn more in our FAQ below!

Once inside the mitochondrion, the dominant way that the bound fatty acids are used as fuel in cells is through β-oxidation, which cleaves two carbons off of the acyl-CoA molecule in every cycle to form acetyl-CoA.[24] Acetyl-CoA enters the citric acid cycle, where it undergoes an aldol condensation with oxaloacetate to form citric acid; citric acid then enters the tricarboxylic acid cycle (TCA), which harvests a very high energy yield per carbon in the original fatty acid.[25][26] 

First reported in 2003, the idea of using a form of the Atkins diet to treat epilepsy came about after parents and patients discovered that the induction phase of the Atkins diet controlled seizures. The ketogenic diet team at Johns Hopkins Hospital modified the Atkins diet by removing the aim of achieving weight loss, extending the induction phase indefinitely, and specifically encouraging fat consumption. Compared with the ketogenic diet, the modified Atkins diet (MAD) places no limit on calories or protein, and the lower overall ketogenic ratio (about 1:1) does not need to be consistently maintained by all meals of the day. The MAD does not begin with a fast or with a stay in hospital and requires less dietitian support than the ketogenic diet. Carbohydrates are initially limited to 10 g per day in children or 20 g per day in adults, and are increased to 20–30 g per day after a month or so, depending on the effect on seizure control or tolerance of the restrictions. Like the ketogenic diet, the MAD requires vitamin and mineral supplements and children are carefully and periodically monitored at outpatient clinics.[48]

Might not be nutritional. Could be a training issue. Could be fascial. Could be neurotransmitter. If you're taking 1 serving of UCAN perhaps you need two. Not sure of ht, body wt, etc. 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.
I was shocked at how easy it was (using the new supplements and methods outlined below that have been developed since my initial foray into ketosis) to get into ketosis without extreme carbohydrate restriction, without excessive, diarrhea and “diaper-moment” inducing amounts of MCT and coconut oil, and without the inflammation, triglyceride and hormonal issues, or social discomfort I outline above. I was also able to achieve a much more immediate and deeper level of ketosis than I ever achieved in previous experiments sans these newer strategies you’re going to learn about.
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