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]
This article is excellent and I’ve actually read it a few times just to make sure I’m absorbing as much as possible. With that said can we talk a bit about protein? Why does it seem like protein is taking a back seat? What about the athlete who needs to maintain and/or increase muscle mass. I don’t want to make any assumptions and with all the research I’ve done along with personal testing into Keto it just seems to me that protein and its benefits are not a discussion point in this diet. Why?
After that happened, I set out once again to find some kind of carbohydrate source that allows one to maintain elevated liver glycogen and muscle glycogen stores without getting all the blood-sugar level roller coaster rides or gut rot and fermentation that many typical sports nutrition carbohydrate sources such as fructose and maltodextrin can cause.
Considered a symptom of the keto flu, your breath on this diet often smells fruity at first. This is because acetone is a by-product of ketosis and is eliminated mostly through the lungs and the breath, according to a study in the journal International Journal of Environmental Research and Public Health in February 2014. Acetone is a type of ketone known for having a fruity aroma in smaller concentrations. “It’s hard to say exactly how long it will last as it depends on the person, but it’s common for someone to experience this side effect for a few weeks,” says Asche.
Ketosis is deliberately induced by use of a ketogenic diet as a medical intervention in cases of intractable epilepsy.[12] Other uses of low-carbohydrate diets remain controversial.[14][15] Carbohydrate deprivation to the point of ketosis has been argued to have both negative[16] and positive effects on health.[17][18] Ketosis can also be induced following periods of fasting (starvation),[19] and after consumption of ketogenic fats (such as medium chain triglycerides[citation needed]) or exogenous ketones.[20]
Remember how important it is to measure ketone blood levels accurately? Same goes for food tracking. A food tracking app, like MyFitnessPal, provides insight into macronutrient intake and thus the ability to tweak the diet to achieve ketosis. Tracking diet (inputs) and measuring ketones levels (outputs) delivers the best shot at optimizing the keto diet plan.
1. If a set number ketones in the blood is an indicator that my body has transitioned to ketosis and not necessarily the cause (the cause being limited access to glycogen because of limited carb intake) then how does using exogenous ketones put me in ketosis as opposed to mimic being in ketosis (because when measuring blood ketones suddenly there are more because I put them there, I didn’t create them)?
The first modern study of fasting as a treatment for epilepsy was in France in 1911.[12] Twenty epilepsy patients of all ages were "detoxified" by consuming a low-calorie vegetarian diet, combined with periods of fasting and purging. Two benefited enormously, but most failed to maintain compliance with the imposed restrictions. The diet improved the patients' mental capabilities, in contrast to their medication, potassium bromide, which dulled the mind.[13]
Then one night, it all changed. I poured honey and water into a 42-ounce canister of Quaker oats and kept spooning because there was no other carb source in the house. Something strange had possessed me; I would later hear other binge eaters call this “blacking out,” or feeling such intense relief and disinhibition that you consume ridiculous quantities of food without fully realizing or experiencing it. At the time, I remember thinking something was very, very wrong, but the thing that was wrong was my lack of self-control and that I would be better -- keto!!! -- forevermore. And then I did it again a few nights later. I gained weight. I gave up on dieting eventually, but it took me years to reestablish a healthy relationship with food.
Let’s meditate for a second. Close your eyes. What do you see when you picture yourself on keto? Naturally, carb deprivation has carved out Michelangelo's David from your block of pudgy carrara marble. You have so much more energy now, thanks to the chunk of grass-fed butter (or ghee!) you’ve slid into your morning coffee. You're so spry, in fact, that you’re considering investing in bitcoin even though you’re late to the game, or writing a novel even though you don’t read, or getting into a relationship just because you’re overwhelmed by the trove of eligible suitors now bashfully small-smiling at you on public transport.
Some clinicians[37] regard eliminating carbohydrates as unhealthy and dangerous.[38] However, it is not necessary to eliminate carbohydrates from the diet completely to achieve ketosis. Other clinicians regard ketosis as a safe biochemical process that occurs during the fat-burning state.[35] Ketosis, which is accompanied by gluconeogenesis (the creation of glucose de novo from pyruvate), is the specific state that concerns some clinicians. However, it is unlikely for a normally functioning person to reach life-threatening levels of ketosis, defined as serum beta-hydroxybutyrate (B-OHB) levels above 15 millimolar (mM) compared to ketogenic diets among non diabetics, which "rarely run serum B-OHB levels above 3 mM."[39] This is avoided with proper basal secretion of pancreatic insulin. People who are unable to secrete basal insulin, such as type 1 diabetics and long-term type II diabetics, are liable to enter an unsafe level of ketosis, eventually resulting in a coma that requires emergency medical treatment.[citation needed] The anti-ketosis conclusions have been challenged by a number of doctors and advocates of low-carbohydrate diets, who dispute assertions that the body has a preference for glucose and that there are dangers associated with ketosis.[40][41]
Note that urine measurements may not reflect blood concentrations. Urine concentrations are lower with greater hydration, and after adaptation to a ketogenic diet the amount lost in the urine may drop while the metabolism remains ketotic. Most urine strips only measure acetoacetate, while when ketosis is more severe the predominant ketone body is β-hydroxybutyrate.[36] Unlike glucose, ketones are excreted into urine at any blood level. Ketoacidosis is a metabolic derangement that cannot occur in a healthy individual who can produce insulin, and should not be confused with physiologic ketosis.
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
I knew keto was on the The Today Show when relatives began dropping the term in the same charming way your grandmother might refer to “the Instagram.” They knew it was low carb and that it worked, because that’s what the show told them. But they couldn’t explain the state of “ketosis” or why their Yummy Yummy Dark Chocolate Sea Salt Breakfast Replacement Keto Bar was a better choice for weight loss than, like, cutting back on alcohol.
Hello, may I ask if someone has some experience week fasting for 14 days? I was told that the food which should be started taken after 14 days of fasting has to be in very simple and in slow amount. Unfortunately 1-2 days after fasting I am allowed to take only bouillon out of buckwheat, barley, from the 3rd day buckwheat mush, and only from 5th day milk or sour cream, oil since 11th day. Can anyone advice how should I adopt this come back food path to Ketogenic diet? Thank you in advance, Maria

Along with biomarker testing, subjective symptoms can provide an indication of your ketosis. Sometimes, early side effects of the diet result from carbohydrate withdrawal. This can be known as the "keto flu;" symptoms include nausea, fatigue, headache and dry mouth. They're short-term, typically lasting about a week or less. Keep in mind, however, that we are all different. Our bodies react in different ways. Some of us may experience these symptoms later than sooner, to a lesser extent, or not at all.
If I see a TSH above 2.0 or a trend towards higher values in someone who is testing repeatedly, I get worried – and prefer to see TSH at 0.5-2.0. Of course, this doesn’t mean that you begin to shove carbohydrates indiscriminately down the hatch. However, it means that your high-fat, low-carb diet should include thyroid supporting foods rich in iodine and selenium, such as sea vegetables and brazil nuts, and should also include carbohydrates timed properly, such as before, during or after workouts, when the carbohydrate is more likely to be utilized for energy and less likely to spike blood glucose levels.

On a ketogenic diet, your entire body switches its fuel supply to run mostly on fat, burning fat 24-7. When insulin levels become very low, fat burning can increase dramatically. It becomes easier to access your fat stores to burn them off. This is great if you’re trying to lose weight, but there are also other less obvious benefits, such as less hunger and a steady supply of energy. This may help keep you alert and focused.
2) I'm currently using Ketocana and in that section you state "Similar to the BHB salts and MCT’s from the KETO//OS I discuss above, powdered forms of ketones are excellent if you don’t want to completely eliminate carbohydrates or fat or eat copious amounts of fats, but want to simultaneously maintain high levels of blood ketones." – How would eating copious amounts of fat be a negative? Wouldn't that help contribute to a ketogenic state?
Since the body’s acid-base buffering system cannot neutralize the vast amount of acidic ketones, the blood pH drops significantly. This buildup of acids in the blood poisons the body and can lead to ketoacidosis.12 Breathing becomes deep and rapid as the body attempts to compensate for excessive acids. Other symptoms of diabetic ketoacidosis include:
Hi I’m new to Keto. I have been reading about it, and understanding what to eat and what not to eat. My problem is I’m not sure if I’m doing it correctly. I’m constantly hungry whereas information reads that I will never be hungry. I use fats as required along with topping up with vegetables in my meals yet this does not fill me up. I haven’t experienced the Keto flu and I’ve even put on weight! I have been doing this for about 3 weeks now. Any ideas where I am going wrong.
Those new to keto should be testing to see if their bodies are in ketosis, regardless of method. Testing, in general, is the most objective way to know if you’re in ketosis. There can be some subjective benefits of ketosis: appetite suppression, fat loss, low blood sugar, improvement in mental cognition and focus. But before recognizing these subjective benefits, it’s important to track and measure the level of ketones in the blood to ensure ketosis on a physical level.
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!
Keto-adaptation, AKA “becoming a fat burning machine”, occurs when you have shifted your metabolism to relying on fat-based sources, instead of glucose (sugar) sources, as your primary source of fuel. Your body increases fat oxidation, and breaks down fats into ketones to be used as the primary energy source. Depending on your current level of carbohydrate intake (takes longer if you’re pretty sugar addicted), this process can take two weeks to six months to fully train your body to, but once done, it’s done, and you have achieved fat-burning status that can stick with you for life.

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


Cyclical keto diet: The Bulletproof Diet falls into this category. You eat high fat, low carb (less than 50 grams of net carbs a day) five to six days of the week. On day seven, you up your carb intake to roughly 150 grams, during what’s called a carb refeed day. Carb cycling this way helps you avoid the negative effects some people experience when they restrict carbs long term, like thyroid issues, fatigue and dry eyes.[9][10]  Learn more here about how carb cycling works.
The ketogenic diet reduces seizure frequency by more than 50% in half of the patients who try it and by more than 90% in a third of patients.[18] Three-quarters of children who respond do so within two weeks, though experts recommend a trial of at least three months before assuming it has been ineffective.[9] Children with refractory epilepsy are more likely to benefit from the ketogenic diet than from trying another anticonvulsant drug.[1] Some evidence indicates that adolescents and adults may also benefit from the diet.[9]
-Cardiovascular Disease: High blood sugar has been shown to increase the risk for cardiovascular events, cardiovascular disease, and cardiovascular mortality—while lower glucose levels result in lower cardiovascular risk. Coronary artery disease risk has been shown to be twice as high in patients with impaired glucose tolerance, compared with patients with more normal glucose tolerance. The risk for stroke increases as fasting glucose levels rise above 83 mg/dL. In fact, every 18 mg/dL increase beyond 83 results in a 27 percent greater risk of dying from stroke. Incidentally, glucose can “stick” to cholesterol particles and render these particles extremely dangerous from a heart health standpoint, which is why it’s all the more important to control blood sugar levels if you’re eating a “high-fat diet.”
I have been taking Ucan 30 Minutes before run and take UCAN 1 Hour into run and 1 hour later. Also take BCAA powder in 8 ounce liquid during run. I have been doing HFAT and LCARB diet. Problem i slow down after 1 1/2 hour during my long run. I need your advice help fueling my run after 14 miles. This my first Marathon, I have run 7 Half Marathon around 1.58.
Urine test for diabetes: What you need to know Urine tests for diabetes check for protein, ketones, and glucose. They are frequently used for diagnosing and monitoring diabetes, and to assess people who are experiencing symptoms, such as fatigue or nausea. Depending on the results, recommendations may be given about medication or lifestyle changes that could help. Read now
2) I'm currently using Ketocana and in that section you state "Similar to the BHB salts and MCT’s from the KETO//OS I discuss above, powdered forms of ketones are excellent if you don’t want to completely eliminate carbohydrates or fat or eat copious amounts of fats, but want to simultaneously maintain high levels of blood ketones." – How would eating copious amounts of fat be a negative? Wouldn't that help contribute to a ketogenic state?

The DNA test does not necessarily take into account your goals (e.g. breathholding, Ironman, cognition, etc.) and if your goals would benefit from ketosis, then you may want to choose it as a dietary strategy even though it could indeed be true that for FAT LOSS a higher carb intake may suit you. So it all depends on your goals. Or you could just us the supplements like ketones AND eat more carbs and get "best of both worlds".
Ben. I do not read epidemiological studies anymore… Just biology. There are plenty of examples of traditional cultures consuming high carb (and high fat) without any of the health issues those studies in your article claim. So either high fat or high carb both work if done properly… AND in the right environment. Both are ancestral not just one of the two and have posit and negat because it has to do with the climate and environment around. I do not listen to anybody that pushes JUST one because they are ignoring the reality. I hope you join this "common sense" wagon.
To get the most benefit from the Keto diet, you should stay physically active. You might need to take it easier during the early ketosis period, especially if you feel fatigued or lightheaded. Walking, running, doing aerobics, weightlifting, training with kettlebells or whatever workout you prefer will boost your energy further. You can find books and online resources on how to adapt Keto meals or snacks for athletic training.
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]
Basically, the proven science is in the pudding. A highly cited low-carb study from The New England Journal of Medicine concludes with the statement, “The low-carbohydrate diet produced a greater weight loss (absolute difference, approximately 4 percent) than did the conventional diet for the first six months, but the differences were not significant at one year.” The study mentions health benefits from the low carb diet, of course, but that it’s largely unsustainable.

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.


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.
In addition, most studies that compare carbohydrate utilization with fat utilization fail to take into account the fact that full “fat adaptation” that allows you to gain all the benefits of using fat as a fuel actually takes time – often more than four weeks – and up to a couple years. But since most studies that compare fat and carbohydrate burning are short-term, you rarely see the benefits of this kind of fat adaptation actually fleshed out in research. Instead, the average research participant begins the study in a non-fat adapted state, gets either a high fat or high carb diet, then launches into exercise. But in an ideal study, that person would have followed either a high-fat or high-carb diet for many months before getting their fat burning capability investigated.
Big Think and Lumina Foundation are joining together to identify and help scale leading innovations in education after high school. We are looking to introduce social entrepreneurs with the most innovative solutions in post-high school education to the world. Winners will receive a free trip to New York to receive media training from Big Think’s producers and a team of social venture advisors. From there, your business pitch will be filmed as a real Big Think clip and shared with the world.
^ 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.

Checking your ketone level is one way to know if you’re in ketosis. This metabolic state usually kicks in after three or four days of restricting your carbohydrate intake or going through periods of intermittent fasting. You don’t have to visit a doctor to measure your level. Pick up a ketone urine test from a nearby drug store, or use a blood sugar meter that’s capable of measuring ketones.


I am trying to get back into keto. I did it before and I was so happy when I lost 10lbs (I did the keto for a month). I am ready to go back to this lifestyle. All this information is very helpful, I have written it all down so it can be easier for me to remember what is allowed and what is not. Looking forward to get back on this keto journey. Thank you for all the great info.
Sleep enough – for most people at least seven hours per night on average – and keep stress under control. Sleep deprivation and stress hormones raise blood sugar levels, slowing ketosis and weight loss a bit. Plus they might make it harder to stick to a keto diet, and resist temptations. So while handling sleep and stress will not get you into ketosis on it’s own, it’s still worth thinking about.
Normal dietary fat contains mostly long-chain triglycerides (LCTs). Medium-chain triglycerides (MCTs) are more ketogenic than LCTs because they generate more ketones per unit of energy when metabolised. Their use allows for a diet with a lower proportion of fat and a greater proportion of protein and carbohydrate,[18] leading to more food choices and larger portion sizes.[4] The original MCT diet developed by Peter Huttenlocher in the 1970s derived 60% of its calories from MCT oil.[15] Consuming that quantity of MCT oil caused abdominal cramps, diarrhea, and vomiting in some children. A figure of 45% is regarded as a balance between achieving good ketosis and minimising gastrointestinal complaints. The classical and modified MCT ketogenic diets are equally effective and differences in tolerability are not statistically significant.[9] The MCT diet is less popular in the United States; MCT oil is more expensive than other dietary fats and is not covered by insurance companies.[18]
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?
A ketogenic diet helps control blood sugar levels. It is excellent for managing type 2 diabetes, sometimes even leading to complete reversal of the disease. This has been proven in studies. It makes perfect sense since keto lowers blood-sugar levels, reduces the need of medications and reduces the potentially negative impact of high insulin levels.
Thank you for this article as it cleared up a bunch of stuff for me. I started trying to get into ketosis back in August and lost 20lbs in about 6 weeks. Then it all stopped but had another 20lbs I wanted to loose. I had a hard time staying in ketosis and gave up about a week ago with the holidays approaching. Anyways I glazed over all the technical and science facts as it makes my head spin and might of missed it but my only question is what is the food portion of the diet like? The drinks are the easy part, do you have a diet plan that is good for someone that hits the gym hard 4-5 days a week for and hour and half. 45 min weights and 30-45 min cardio? It’s what I struggle with most the food and what attracted me to a ketogenic diet in the first place is eating 1 or 2 meals a day and being satisfied.
I'd recommend starting with glucose and hemoglobin A1C, along with a good multi like https://bengreenfieldfitness.com/multi and a fish oil like the one at greenfieldfitnesssystems.com – Anyways, 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.
Ben. I do not read epidemiological studies anymore… Just biology. There are plenty of examples of traditional cultures consuming high carb (and high fat) without any of the health issues those studies in your article claim. So either high fat or high carb both work if done properly… AND in the right environment. Both are ancestral not just one of the two and have posit and negat because it has to do with the climate and environment around. I do not listen to anybody that pushes JUST one because they are ignoring the reality. I hope you join this "common sense" wagon.
Elevated blood ketone levels is the sign of ketosis, while certain subjective symptoms can also signal ketosis. Increased mental clarity, less brain fog, and diminished appetite are fairly common among people in ketosis. The ketogenic diet specifically has its own assortment of symptoms. Fortunately, the negative symptoms such as constipation, diarrhea, and bad breath are often temporary and tend fade as your body becomes better at fat burning and naturally producing ketones. The positive symptoms of ketosis coincide with higher levels of ketones in the blood. This may occur after several weeks of adhering to the ketogenic diet or very shortly after ingesting exogenous ketones.
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