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 second type of cellular fuel comes from fat and fat metabolism products called ketone bodies.   The average sized human body can store hundreds of thousands of calories in the form of fat, so we could say that this system of energy is almost unlimited, depending on how long one goes without food.  Eventually, it would get used up, but people have been known to fast for months and live through it.
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.
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]
I see a lot of people say that ketosis is great for insulin sensitivity. BUT, in my experience ketosis causes physiological insulin resistance whereby the muscles and liver are sparing glucose for the brain. Hence, glucose tolerance actually goes down during ketosis. As such, is it possible that post workout carbs could do a lot more damage than they would on a non-ketogenic diet? Or maybe, as Kiefer suggests, glucose uptake post workout is not moderated by insulin at all i.e. muscles soak up glucose regardless of their insulin sensitivity? Or maybe cyclical ketosis doesn’t allow liver glycogen to get low enough to trigger physiological insulin resistance?
Wow! Amazing article. I don’t read blogs regularly, but I’ll be reading more of yours. I am on day 11 of a fast to get me into ketosis; 7 days bone broth and now on day-4 water only. Intentions are weight loss (10# down, 15# more to go) and immunity improvement/gut help. Planning 9 days of whey water, fermented veggies and mad probiotics when the water days are done (day 14?). After this fast I want to stay fat adapted, start training again and get down to 8% body fat. I believe you have cut that journey significantly with this article. Thank you.
Meat – like grass-fed selections – and fresh veggies are more expensive than most processed or fast foods. What you spend on Keto-friendly foods will vary with your choices of protein source and quality. You can select less-expensive, leaner cuts of meat and fatten them up with some oil. Buying less-exotic, in-season veggies will help keep you within budget.
Some research suggests that ketogenic diets might help lower your risk of heart disease. Other studies show specific very-low-carb diets help people with metabolic syndrome, insulin resistance, and type 2 diabetes. Researchers are also studying the effects of these diets on acne, cancer, polycystic ovary syndrome (PCOS), and nervous system diseases like Alzheimer's, Parkinson's, and Lou Gehrig's disease.
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)
The Keto diet emphasizes weight loss through fat-burning. The goal is to quickly lose weight and ultimately feel fuller with fewer cravings, while boosting your mood, mental focus and energy. According to Keto proponents, by slashing the carbs you consume and instead filling up on fats, you safely enter a state of ketosis. That’s when the body breaks down both dietary and stored body fat into substances called ketones. Your fat-burning system now relies mainly on fat – instead of sugar – for energy. While similar in some ways to familiar low-carb diets, the Keto diet’s extreme carb restrictions – about 20 net carbs a day or less, depending on the version – and the deliberate shift into ketosis are what set this increasingly popular diet apart.
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?
I am not a doctor and this is not to be taken, interpreted or construed as medical advice. Please talk with a licensed medical professional about this. These are just my own personal thoughts and not a prescription or a diagnosis or any form of health care whatsoever. Your mother can avoid the "keto flu" by adding sufficient sodium to her diet and staying well hydrated, especially in the first few days of starting to reduce carbohydrates. The keto flu could also be called “carbohydrate withdrawal symptoms” because of the effects on hormonal and electrolyte balance. If you're not already using a device to measure ketones in your body, I recommend this one: https://bengreenfieldfitness.com/ketonix As far as how much to take, it all depends….you can actually do more than two servings per day if you want, and you can experiment to see how many servings your body should handle. You should know that it would be very difficult to overdose on ketones. They are water soluble, so any excess ketones will be eliminated mainly via the urine. Hope this helps!
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]

^ 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

The ketogenic diet typically reduces carbohydrate intake to less than 50 grams per day — and calls for increased protein and fat intake, according to a review published in August 2013 in the European Journal of Clinical Nutrition. Roughly speaking, on keto you’ll get 70 to 80 percent of your calories from fat, about 20 percent from protein, and as little as 5 percent from carbs.

Weight loss is my favorite side effect of keto. Coming in a close 2nd, 3rd, and 4th, and 5th is higher energy levels, no bingeing, clear skin, and lowered blood glucose! I don’t mind telling people that I’m Keto...or shutting down a conversation where they try and spew their online doctor degree about how I’m killing myself. This WOE work is for me, my bloodwork is the best it has ever been, and I feel great. Keto on, friends.
The ketogenic diet typically reduces carbohydrate intake to less than 50 grams per day — and calls for increased protein and fat intake, according to a review published in August 2013 in the European Journal of Clinical Nutrition. Roughly speaking, on keto you’ll get 70 to 80 percent of your calories from fat, about 20 percent from protein, and as little as 5 percent from carbs.
And it all culminated with me stepping into Dr. Jeff Volek’s world famous laboratory at University of Connecitut to subject myself to extensive blood testing, chunks of muscle removed from my legs, fat sucked out of my butt-cheeks, urine, stool and gut microbiome testing, oxygen and carbon dioxide testing and countless hours of treadmill running to discover what a full twelve months of eating a ketotic diet had actually done to my body.
Protein will induce an insulin response in the body, if consumed in high amounts. The most intuitive way to start a keto diet for most people is by removing all of the carbs they have been eating. Typically people will replace those calories by increasing their lean meat consumption. That's a recipe for disaster! Keeping protein moderate is an often overlooked, but very important part of a keto diet. Most people need around 0.6g to 1.0g of protein per pound of lean body mass.

Note: Because you'll be excluding some major food groups on the keto diet (grains, many fruits) you should definitely think about taking a multivitamin—especially one that contains folic acid, which helps your body make new cells and is often found in enriched breads, cereals, and other grain products, says Julie Upton, R.D., cofounder of nutrition website Appetite for Health.
Now, there a few things you should know before you begin using KETO//OS. First, ketones naturally act as a diuretic, so you lose salt, potassium, calcium and magnesium, and it is generally encouraged to increase sodium intake with ketones. That’s why there is extra sodium added to KETO//OS. The combination of BHB with sodium also acts as a bit of a buffer to buffer natural ketone acidity.
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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?
About 20% of children on the ketogenic diet achieve freedom from seizures, and many are able to reduce the use of anticonvulsant drugs or eliminate them altogether.[18] Commonly, at around two years on the diet, or after six months of being seizure-free, the diet may be gradually discontinued over two or three months. This is done by lowering the ketogenic ratio until urinary ketosis is no longer detected, and then lifting all calorie restrictions.[46] This timing and method of discontinuation mimics that of anticonvulsant drug therapy in children, where the child has become seizure-free. When the diet is required to treat certain metabolic diseases, the duration will be longer. The total diet duration is up to the treating ketogenic diet team and parents; durations up to 12 years have been studied and found beneficial.[9]
Some Inuit consume as much as 15–20% of their calories from carbohydrates, largely from the glycogen found in raw meats.[43][44][47][45][50] Furthermore, the blubber, organs, muscle and skin of the diving marine mammals that the Inuit eat have significant glycogen stores that are able to delay postmortem degradation, particularly in cold weather.[51][52][53][54][55][56]
Infants and patients fed via a gastrostomy tube can also be given a ketogenic diet. Parents make up a prescribed powdered formula, such as KetoCal, into a liquid feed.[19] Gastrostomy feeding avoids any issues with palatability, and bottle-fed infants readily accept the ketogenic formula.[31] Some studies have found this liquid feed to be more efficacious and associated with lower total cholesterol than a solid ketogenic diet.[18] KetoCal is a nutritionally complete food containing milk protein and is supplemented with amino acids, fat, carbohydrate, vitamins, minerals and trace elements. It is used to administer the 4:1 ratio classic ketogenic diet in children over one year. The formula is available in both 3:1 and 4:1 ratios, either unflavoured or in an artificially sweetened vanilla flavour and is suitable for tube or oral feeding.[51] Other formula products include KetoVolve[52] and Ketonia.[53] Alternatively, a liquid ketogenic diet may be produced by combining Ross Carbohydrate Free soy formula with Microlipid and Polycose.[53]
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.
Hey Alex, thanks for commenting and great to have you as a new listener! For this kind of thing, because it requires so going into detail, I'd suggest you book a consult with me by going to
If you would like to read more on ketogenic diets and ketosis, Jeff Volek and Steve Phinney discuss the new method of checking blood ketones in their book "The Art and Science of Low Carbohydrate Performance", and they also offer another good book "The Art and Science of Low Carbohydrate Living", which is a good book for those who need an introduction to the science of ketogenic diets.