Even hibernating bears do not go into ketosis[2]. And predatory animals who undergo extended periods of food deprivation, such as elephant seals[3], are metabolically resistant to ketosis; instead, they have upregulated gluconeogenesis pathways through which they can steadily produce glucose. This makes perfect sense, since predators’ survival depends on their ability to catch their prey, which usually requires intense bursts of activity. And sprinting capacity is dependent on glucose, as humans who adopt a ketogenic diet quickly discover.
I’m following the ketogenic diet and I find it very easy, pleasant and varied. I can even say that my diet today is more varied than the previous one. I do not intend to leave this diet and I cannot really see why. My initial focus was not to lose weight, I’ve always been lean, but to feel better, well disposed. And I got it! I am very pleased, I have read a lot about it (including scientific literature) and I have influenced other people who need to lose weight or improve some aspects of their health. But from the beginning I went on my own way, without the help of a nutritionist because I did not want to suffer the influence of others’ ideas.
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]

A study with an intent-to-treat prospective design was published in 1998 by a team from the Johns Hopkins Hospital[20] and followed-up by a report published in 2001.[21] As with most studies of the ketogenic diet, no control group (patients who did not receive the treatment) was used. The study enrolled 150 children. After three months, 83% of them were still on the diet, 26% had experienced a good reduction in seizures, 31% had had an excellent reduction, and 3% were seizure-free.[Note 7] At 12 months, 55% were still on the diet, 23% had a good response, 20% had an excellent response, and 7% were seizure-free. Those who had discontinued the diet by this stage did so because it was ineffective, too restrictive, or due to illness, and most of those who remained were benefiting from it. The percentage of those still on the diet at two, three, and four years was 39%, 20%, and 12%, respectively. During this period, the most common reason for discontinuing the diet was because the children had become seizure-free or significantly better. At four years, 16% of the original 150 children had a good reduction in seizure frequency, 14% had an excellent reduction, and 13% were seizure-free, though these figures include many who were no longer on the diet. Those remaining on the diet after this duration were typically not seizure-free, but had had an excellent response.[21][22]
A ketogenic diet is a very low-carbohydrate way of eating that delivers moderate amounts of high-quality dietary protein and high amounts of healthy dietary fat. This reduction in carbohydrate intake helps the body shift toward a state that promotes the breakdown of fats (from the diet and your body) to produce ketone bodies and enter a state known as “ketosis.”
Your glycogen stores can still be refilled while on a ketogenic diet. A keto diet is an excellent way to build muscle, but protein intake is crucial here. It’s suggested that if you are looking to gain mass, you should be taking in about 1.0 – 1.2g protein per lean pound of body mass. Putting muscle on may be slower on a ketogenic diet, but that’s because your total body fat is not increasing as much.5Note that in the beginning of a ketogenic diet, both endurance athletes and obese individuals see a physical performance for the first week of transition.
Type 2 diabetes. One study found that being on the keto diet for one year reversed diabetes for up to 60 percent of participants. With an average weight loss of 30 pounds, they dramatically reduced or eliminated their need for insulin and no longer needed oral hypoglycemic drugs. The keto diet is also easier to sustain than the calorie-restricted diet or the protein-sparing modified fast.
You may spot low-carb and sugar-free ice cream in your grocery store’s freezer case. Take one look at the ingredients, though, and you’ll find artificial colors, potentially moldy corn products, and sucralose that can harm your gut bacteria. This version tastes like a dirty keto recipe, but sweetens the results with grass-fed butter, collagen protein, and simple flavors like cocoa powder and cinnamon.
Thanks for this article. I just started a Keto diet so found it appropriate to my current lifestyle. Though I don’t believe your bottom line is strong enough since you simply stating that the diet is “hard to follow” and food is “notoriously unhealthy” without evidence going deeper into why those “notoriously unhealthy” foods are worse than keeping carbohydrate-heavy food that are addictive and give the body a quick sugar high for energy. I believe “hard to follow” is your opinion only, since acceptable Keto foods are found at all restaurants easily and also all grocery stores. All the foods you mention: “rich in very colorful fruits and vegetables, lean meats, fish, whole grains, nuts, seeds, olive oil, and lots of water” are all Keto-friendly. Many people have been on a Keto-diet for years. A healthy lifestyle is a healthy mindset change and making right choices – it’s not going to be easy.

A slew of articles in recent months have referred to the ketogenic diet as a “fad” or “trend.” It’s “dangerous,” claimed one article, and an anonymous post by the Harvard Public School of Public Health said the diet “comes with serious risks.”1 Yet strangely, these critics seldom cite scientists or doctors who work with the diet, and many—including the Harvard article—cite no medical literature to substantiate their allegations. Without substantiation, many simply rehash long-contradicted, outdated claims.
Over 8–10 mmol/l: It’s normally impossible to get to this level just by eating a keto diet. It means that something is wrong. The most common cause by far is type 1 diabetes, with severe lack of insulin. Symptoms include feeling very sick with nausea, vomiting, abdominal pain and confusion. The possible end result, ketoacidosis, may be fatal and requires immediate medical care. Learn more
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