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Other research further supports the potential benefits of this diet. For example, preliminary studies link following the keto diet to reduced symptoms of Alzheimer’s disease. (4) Previous research suggests it may also help reverse metabolic syndrome, manage Parkinson’s disease, has been proven to help control seizures in children with epilepsy, and, according to the results of a small pilot study, may potentially even improve symptoms of polycystic ovary syndrome (PCOS). (5, 6, 7)
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.

While it is believed that carbohydrate intake after exercise is the most effective way of replacing depleted glycogen stores,[72][73] studies have shown that, after a period of 2–4 weeks of adaptation, physical endurance (as opposed to physical intensity) is unaffected by ketosis, as long as the diet contains high amounts of fat, relative to carbohydrates.[74] Some clinicians refer to this period of keto-adaptation as the "Schwatka imperative" after Frederick Schwatka, the explorer who first identified the transition period from glucose-adaptation to keto-adaptation.[75]

Let’s talk about a keto side effect that may not be so sexy: constipation. “Many of the richest sources of fiber, like beans, fruit, and whole grains are restricted on the ketogenic diet,” says Clark. “As a result, ketogenic eaters miss out on the benefits of fiber-rich diet such as regular laxation and microbiome support. The microbiome has been implicated in everything from immune function to mental health.” Indeed, in a long-term study in the Journal of Pediatrics in April 2015, constipation was noted as a very common side effect in children receiving ketogenic diets for epilepsy treatment.


What is the link between ketones and diabetes? Ketone is a chemical produced by the body when fats are broken down for energy. Ketone testing is important for people with diabetes, because high levels can lead to diabetic ketoacidosis (DKA), when acid levels become too high in the blood and the person loses consciousness. Find out when and why to do ketone testing. Read now

When you eat less than 50 grams of carbs a day, your body eventually runs out of fuel (blood sugar) it can use quickly. This typically takes 3 to 4 days. Then you’ll start to break down protein and fat for energy, which can make you lose weight. This is called ketosis. It's important to note that the ketogenic diet is a short term diet that's focussed on weight loss rather than the pursuit of health benefits. 
The ketogenic diet is a mainstream dietary therapy that was developed to reproduce the success and remove the limitations of the non-mainstream use of fasting to treat epilepsy.[Note 2] Although popular in the 1920s and '30s, it was largely abandoned in favour of new anticonvulsant drugs.[1] Most individuals with epilepsy can successfully control their seizures with medication. However, 20–30% fail to achieve such control despite trying a number of different drugs.[9] For this group, and for children in particular, the diet has once again found a role in epilepsy management.[1][10]
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.
In Asia, the normal diet includes rice and noodles as the main energy source, making their elimination difficult. Therefore, the MCT-oil form of the diet, which allows more carbohydrate, has proved useful. In India, religious beliefs commonly affect the diet: some patients are vegetarians, will not eat root vegetables or avoid beef. The Indian ketogenic diet is started without a fast due to cultural opposition towards fasting in children. The low-fat, high-carbohydrate nature of the normal Indian and Asian diet means that their ketogenic diets typically have a lower ketogenic ratio (1:1) than in America and Europe. However, they appear to be just as effective.[54]

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.

In its 2016 report “Healthy Eating Guidelines & Weight Loss Advice,” the Public Health Collaboration, a U.K. nonprofit, evaluated evidence on low-carbohydrate, high-fat diets. (The Keto diet falls under the LCHF umbrella.) Among 53 randomized clinical trials comparing LCHF diets to calorie-counting, low-fat diets, a majority of studies showed greater weight loss for the Keto-type diets, along with more beneficial health outcomes. The collaboration recommends weight-loss guidelines that include a low-carbohydrate, high-fat diet of real (rather than processed) foods as an acceptable, effective and safe approach.
As a matter of fact, from a pure biology perspective, lauric acid should actually be considered a LCT, because unlike C8 and C10 forms of MCT, lauric acid gets processed by your liver. This matters because your body metabolizes MCT’s differently than LCT’s: unlike LCT’s, MCT’s get very quickly converted into ketone energy to fuel your brain and body instead of requiring a pit stop in the liver for processing.
The ketogenic diet is usually initiated in combination with the patient's existing anticonvulsant regimen, though patients may be weaned off anticonvulsants if the diet is successful. Some evidence of synergistic benefits is seen when the diet is combined with the vagus nerve stimulator or with the drug zonisamide, and that the diet may be less successful in children receiving phenobarbital.[18]
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.
Ben – curious about your thoughts on this. I went into ketosis (using LOTS of coconut oil) but it raised my cholesterol and doc was worried about my lp(a) level (17mg/dL on VAP) even though crp was 0.5, trigs 51 and a1c was 5.2. Advised a low fat diet. Have you seen this before with folks on a lchf/ketosis diet and is there anything to be concerned about? Off to read your coconut oil article. Thank you!
Exogenous ketosis comes from an external source. Consuming exogenous ketones, like a ketone drink containing a ketone ester or a ketone salt, raises blood ketone levels. The body isn't producing ketones in this state, but still remains in ketosis from having ketones introduced from an outside source. However, the body isn't ketogenic–that specifically means the body is producing its own ketones.
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.
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]
Signs of diabetic ketoacidosis include a high blood glucose level, a high ketone level, dehydration, frequent urination, nausea, difficulty breathing, and dry skin. If you have poorly managed type 1 or type 2 diabetes, test your blood glucose level regularly before and after meals, and make sure you check your ketone level whenever your blood sugar is higher than 240 milligrams per deciliter (mg/dL). (11)
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.
Hi Ben great science & sound advice. May I share with the group? I’m 42, in australia, have been an alcoholic for 10 yrs. In April 2016 I gave up drinking & started living strictly ketogenic. In 3 months I dropped 25 kilos. I have cheated on weekends but I go through a fast of sorts on Mondays to get back into ketosis by Tues. I work afternoon / evenings so I wake at 10.30am take a pre workout drink with raspberry ketones & a splash of mct oil & all my vitamins as well. I then do weights for an hr then get ready to go to work. I take 2 800ml protein shakes consisting of 20 ml mct & 30grm amino enhanced protein. I work in warehousing so I walk anywhere between 10 km & 5 km a nite. I feel great all the time, thanks largely to your research & advice. If have any thoughts or opinions I’d love hear them.
The nerve impulse is characterised by a great influx of sodium ions through channels in the neuron's cell membrane followed by an efflux of potassium ions through other channels. The neuron is unable to fire again for a short time (known as the refractory period), which is mediated by another potassium channel. The flow through these ion channels is governed by a "gate" which is opened by either a voltage change or a chemical messenger known as a ligand (such as a neurotransmitter). These channels are another target for anticonvulsant drugs.[7]
Bulk buy and cook. If you’re someone who doesn’t like to spend a lot of time in the kitchen, this is the best of both worlds. Buying your food at bulk (specifically from wholesalers) can reduce the cost per pound tremendously. Plus, you can make ahead food (bulk cook chicken thighs for pre-made meat, or cook entire meals) that are used as leftovers, so you spend less time cooking.
I’ve been on and off of my Keto diet with the primary purpose of losing weight. I’m 30 years old, workout daily – I’m in decent shape but have some extra fat around the mid-section that I’d like to get rid of, I am hoping to lose ~20 pounds of fat. However, the problem is that I am an extremely picky eater with tremendous cravings for some of my favorite carb-heavy foods – I only eat a number of high-fat / low-carb foods that help me attain Ketosis, so cycling through them multiple times a week becomes excruciating. I find myself cheating on my diet every 2 – 3 weeks, which causes a 3 – 5 pound setback that takes me a few days to overcome and get back into ketosis.
In the 1960s, medium-chain triglycerides (MCTs) were found to produce more ketone bodies per unit of energy than normal dietary fats (which are mostly long-chain triglycerides).[15] MCTs are more efficiently absorbed and are rapidly transported to the liver via the hepatic portal system rather than the lymphatic system.[16] The severe carbohydrate restrictions of the classic ketogenic diet made it difficult for parents to produce palatable meals that their children would tolerate. In 1971, Peter Huttenlocher devised a ketogenic diet where about 60% of the calories came from the MCT oil, and this allowed more protein and up to three times as much carbohydrate as the classic ketogenic diet. The oil was mixed with at least twice its volume of skimmed milk, chilled, and sipped during the meal or incorporated into food. He tested it on 12 children and adolescents with intractable seizures. Most children improved in both seizure control and alertness, results that were similar to the classic ketogenic diet. Gastrointestinal upset was a problem, which led one patient to abandon the diet, but meals were easier to prepare and better accepted by the children.[15] The MCT diet replaced the classic ketogenic diet in many hospitals, though some devised diets that were a combination of the two.[10]
Carbohydrates help control blood sugar levels, which are of particular importance for people with diabetes. A study published in May 2018 in the journal Diabetic Medicine shows that while a keto diet may help control HbA1c levels (a two- to three-month average of blood sugar levels), the diet may also cause episodes of hypoglycemia, which is a dangerous drop in blood sugar. Echoing many registered dietitians, the Lincoln, Nebraska–based sports dietitian Angie Asche, RD, says she is “hesitant to recommend a ketogenic diet for individuals with type 1 diabetes.”
I don’t know about you, but I find these risks pretty damn concerning. The fact is that I want to be around to play with my grandkids, and considering that my genetic testing with 23andMe has revealed that I have a higher-than-normal risk for type 2 diabetes, I doubt that shoving more gooey gels and sugary sports drinks into my pie hole is going to do my health any favors. So if I can achieve similar levels of performance and body composition with carbohydrate restriction, I’m all in.
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]

I know, I know you’d think with all these side effects I’d just give up on ketosis! but I enjoy the mental clarity and I have a lot of food sensitivities and gut and yeast problems and don’t tolerate carbs well either so I feel stuck between a rock and a hard place. Not craving what I can’t have constantly is LIFE CHANGING! (34 year old female with chronic fatigue, thin, hike for exercise).
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.
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!!!
I started a ketogenic diet about 5 weeks ago and have experimented with KetoCaNa and KetoForce along with Now Foods MCT oil (which is made of caprylic and capric acid) in the hopes of easing the transition into ketosis. I don’t use it every day, but often before an aerobic based workout. I was wondering if taking these exogenous ketones at the beginning of a ketogenic diet helps you become keto adapted by up regulating the body’s handling of ketones. And conversely, does taking exogenous ketones down regulate or affect lypolysis since BHB is readily available? My main priority at this point is fat loss.
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