" "

This is an absolutely necessary function for basic survival. As the body can only store carbs for a day or two, the brain would quickly shut down after a couple of days without food. Alternatively it would quickly have to convert our muscle protein into glucose – a very inefficient process – just to keep the brain going. That would make us waste away quickly. It would also ensure that the human race could hardly have survived all those millennia before we had 24-7 food availability.

On the ketogenic diet, carbohydrates are restricted and so cannot provide for all the metabolic needs of the body. Instead, fatty acids are used as the major source of fuel. These are used through fatty-acid oxidation in the cell's mitochondria (the energy-producing parts of the cell). Humans can convert some amino acids into glucose by a process called gluconeogenesis, but cannot do this by using fatty acids.[57] Since amino acids are needed to make proteins, which are essential for growth and repair of body tissues, these cannot be used only to produce glucose. This could pose a problem for the brain, since it is normally fuelled solely by glucose, and most fatty acids do not cross the blood–brain barrier. However, the liver can use long-chain fatty acids to synthesise the three ketone bodies β-hydroxybutyrate, acetoacetate and acetone. These ketone bodies enter the brain and partially substitute for blood glucose as a source of energy.[56]
-Pancreatic Dysfunction: The beta cells in the pancreas that produce the insulin to help control blood sugar become dysfunctional with high blood glucose, raising the risk for type 2 diabetes. Researchers have discovered that beta cell issues are detectable in people whose glucose levels spike two hours after eating, despite those levels staying within the range considered normal and safe by the medical establishment.

^ Freeman JM, Vining EP, Pillas DJ, Pyzik PL, Casey JC, Kelly LM. The efficacy of the ketogenic diet—1998: a prospective evaluation of intervention in 150 children. Pediatrics. 1998 Dec;102(6):1358–63. doi:10.1542/peds.102.6.1358. PMID 9832569. https://web.archive.org/web/20040629224858/http://www.hopkinsmedicine.org/press/1998/DECEMBER/981207.HTM Lay summary]—JHMI Office of Communications and Public Affairs. Updated 7 December 1998. Cited 6 March 2008. 

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]
The modified Atkins diet reduces seizure frequency by more than 50% in 43% of patients who try it and by more than 90% in 27% of patients.[18] Few adverse effects have been reported, though cholesterol is increased and the diet has not been studied long term.[48] Although based on a smaller data set (126 adults and children from 11 studies over five centres), these results from 2009 compare favourably with the traditional ketogenic diet.[18]
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.
Early studies reported high success rates; in one study in 1925, 60% of patients became seizure-free, and another 35% of patients had a 50% reduction in seizure frequency. These studies generally examined a cohort of patients recently treated by the physician (a retrospective study) and selected patients who had successfully maintained the dietary restrictions. However, these studies are difficult to compare to modern trials. One reason is that these older trials suffered from selection bias, as they excluded patients who were unable to start or maintain the diet and thereby selected from patients who would generate better results. In an attempt to control for this bias, modern study design prefers a prospective cohort (the patients in the study are chosen before therapy begins) in which the results are presented for all patients regardless of whether they started or completed the treatment (known as intent-to-treat analysis).[19]

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).
The addition of MCT powder to ketones serves the purpose of maintaining endogenous production of ketone bodies by stimulating fatty acid oxidation in the liver, which then causes the production of even more ketone bodies. In this transcript from a podcast with Dr. Dom D’Agostino it is mentioned that MCT’s cross the blood-brain barrier straight to the brain. So not only are the ketones being used by the brain as an alternative fuel but so are MCT’s.
Next, you need to ease yourself into this stuff. As I mentioned earlier, KETO//OS is blended with MCT’s, which can cause digestive distress if you’re not used to consuming them. This is due to the fact that your body has not yet adapted to the increased fats in your diet, and is less efficient at utilizing ketones as its fuel source. Once your body has adapted to MCT in the diet, the digestive distress will resolve.  But I recommend you start slowly with just about a half a serving a day, and over two weeks, build up to a full serving twice a day.
On a low carb or ketogenic diet my fasting blood sugar is 90-120. I think it may get higher the lower carb I go. Most internet sources say don’t worry about it, worry about your Ha1c. Is this insulin resistance? Anyone have better information? If I do a water fast my morning blood sugar will go down and down each day, til it reaches about 50 in 4 days. But as soon as I start eating it pops right back up.
The reason purity matters is that C17 is a byproduct of most MCT oil production processes, and it, along with C6, is a major cause of throat burning and gut irritation. Most MCT’s on the market are manufactured via chemical and solvent based refining, which involves using chemicals like hexane and different enzymes and combustion chemicals, such as sodium methoxide. But ideally, you should get an MCT oil that is made using triple steam distillation in a non-oxygen atmosphere to avoid lipid oxidation and create a purer end-product.
As I learned in a University of Connecticut lab experiment I mentioned earlier in this article (gory details here), a high-fat, low-carb diet can teach and allow the muscles to tap into more fat for fuel, making your body crave less use of oxygen in the large muscles of the legs, arms or other areas that you’ve learned oxygen gets shunted away from when deep underwater.

But wait, there’s one loophole. Have polycystic ovary syndrome (PCOS)? Then the keto diet may help regulate your periods. “Women with PCOS have high insulin levels, which cause sex hormone imbalances,” notes Yawitz. In a small study published in the journal Nutrition & Metabolism, subjects with PCOS following a ketogenic diet for six months noted improvements in their menstrual cycles — and a small number of women became pregnant, overcoming previous infertility obstacles. “This study was very small, so we can’t make recommendations for all women with PCOS based on its findings,” says Yawitz. “And really, any diet that leads to weight loss should help in PCOS.”