In general, a low-carb diet focuses on proteins, including meat, poultry, fish and eggs, and some nonstarchy vegetables. A low-carb diet generally excludes or limits most grains, legumes, fruits, breads, sweets, pastas and starchy vegetables, and sometimes nuts and seeds. Some low-carb diet plans allow small amounts of certain fruits, vegetables and whole grains.

A short-lived increase in seizure frequency may occur during illness or if ketone levels fluctuate. The diet may be modified if seizure frequency remains high, or the child is losing weight.[19] Loss of seizure-control may come from unexpected sources. Even "sugar-free" food can contain carbohydrates such as maltodextrin, sorbitol, starch, and fructose. The sorbitol content of suntan lotion and other skincare products may be high enough for some to be absorbed through the skin and thus negate ketosis.[31]
While cutting down your carb intake all at once may result in faster weight loss, the simple fact is you’re not going to lose any weight unless you stick to that low carb or Keto diet. So, your first priority should be to ensure you’re not going to give up on the diet because you feel too crappy. If that’s going to be the case, then try reducing your carb intake slowly.

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]


The medical community is taking note of the high public interest in keto. An article in the Jan. 16, 2018, Journal of the American Medical Association summarized several areas of promise: Many people feel less hungry on the high-fat keto diet and so may naturally reduce their overall calorie intake. Beyond weight loss, there was good news for diabetes management, with improved insulin sensitivity and blood-sugar control for people following a ketogenic diet in an early, still-ongoing study. However, an editorial appearing online July 15, 2019, in JAMA Internal Medicine concluded that “enthusiasm outpaces evidence” when it comes to a keto diet for obesity and diabetes.
When in the hospital, glucose levels are checked several times daily and the patient is monitored for signs of symptomatic ketosis (which can be treated with a small quantity of orange juice). Lack of energy and lethargy are common, but disappear within two weeks.[17] The parents attend classes over the first three full days, which cover nutrition, managing the diet, preparing meals, avoiding sugar, and handling illness.[19] The level of parental education and commitment required is higher than with medication.[44]
"One of the primary places where you are going to see metabolic changes on any kind of diet is in your gastrointestinal tract -- and that can include a change in bowel habits often experienced as constipation," says Sondike, who is also credited with conducting the first published, randomized clinical trial on low-carb diets. The reason, Sondike tells WebMD, is that most folks get whatever fiber they consume from high-carb foods such as bread and pasta. Cut those foods out, and your fiber intake can drop dramatically, while the risk of constipation rises.
The classic ketogenic diet is not a balanced diet and only contains tiny portions of fresh fruit and vegetables, fortified cereals, and calcium-rich foods. In particular, the B vitamins, calcium, and vitamin D must be artificially supplemented. This is achieved by taking two sugar-free supplements designed for the patient's age: a multivitamin with minerals and calcium with vitamin D.[18] A typical day of food for a child on a 4:1 ratio, 1,500 kcal (6,300 kJ) ketogenic diet comprises three small meals and three small snacks:[28]
Undesirable symptoms may show up in the first few days after changing what you eat. But this should not be the deciding factor when choosing what to put on your plate. Ideally, you should have the most comprehensive and nutritionally dense diet possible, and the Mediterranean and DASH diets have the best evidence to support living a long and healthy life.

Many people have decided to try the ketogenic diet for weight loss. The most recent evidence shows that reducing your carbohydrate intake to a minimum may help you shed a few pounds, at least in the first few weeks to months. However, we don’t really know whether, over the long term, achieving and maintaining ketosis is better for weight loss than other diets. Almost any intervention can cause undesirable consequences, and the ketogenic diet is no different. One of the most well-publicized complications of ketosis is something called “keto flu.”


A small Feb. 20, 2017, study looked at the impact of a six-week ketogenic diet on physical fitness and body composition in 42 healthy adults. The study, published in the journal Nutrition & Metabolism, found a mildly negative impact on physical performance in terms of endurance capacity, peak power and faster exhaustion. Overall, researchers concluded, “Our findings lead us to assume that a [ketogenic diet] does not impact physical fitness in a clinically relevant manner that would impair activities of daily living and aerobic training.” The “significant” weight loss of about 4.4 pounds, on average, did not affect muscle mass or function.
The so-called keto flu is a group of symptoms that may appear two to seven days after starting a ketogenic diet. Headache, foggy brain, fatigue, irritability, nausea, difficulty sleeping, and constipation are just some of the symptoms of this condition, which is not recognized by medicine. A search for this term yields not a single result on PubMed, the library of indexed medical research journals. On the other hand, an internet search will yield thousands of blogs and articles about keto flu.
A systematic review in 2018 looked at 16 studies on the ketogenic diet in adults. It concluded that the treatment was becoming more popular for that group of patients, that the efficacy in adults was similar to children, the side effects relatively mild. However, many patients gave up with the diet, for various reasons, and the quality of evidence was inferior to studies on children. Health issues include high levels of low-density lipoprotein, high total cholesterol, and weight loss.[24]
Another option is to decrease the intake of carbohydrates slowly, over a few weeks, to minimize side effects. But the “Nike way” (Just Do It) may be the best choice for most people. Removing most sugar and starch often results in several pounds lost on the scale within a few days. This may be mostly fluids, but it can still be great for motivation.

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]
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.
Another option is to decrease the intake of carbohydrates slowly, over a few weeks, to minimize side effects. But the “Nike way” (Just Do It) may be the best choice for most people. Removing most sugar and starch often results in several pounds lost on the scale within a few days. This may be mostly fluids, but it can still be great for motivation.
Because the ketogenic diet alters the body's metabolism, it is a first-line therapy in children with certain congenital metabolic diseases such as pyruvate dehydrogenase (E1) deficiency and glucose transporter 1 deficiency syndrome,[35] which prevent the body from using carbohydrates as fuel, leading to a dependency on ketone bodies. The ketogenic diet is beneficial in treating the seizures and some other symptoms in these diseases and is an absolute indication.[36] However, it is absolutely contraindicated in the treatment of other diseases such as pyruvate carboxylase deficiency, porphyria, and other rare genetic disorders of fat metabolism.[9] Persons with a disorder of fatty acid oxidation are unable to metabolise fatty acids, which replace carbohydrates as the major energy source on the diet. On the ketogenic diet, their bodies would consume their own protein stores for fuel, leading to ketoacidosis, and eventually coma and death.[37]
While cutting down your carb intake all at once may result in faster weight loss, the simple fact is you’re not going to lose any weight unless you stick to that low carb or Keto diet. So, your first priority should be to ensure you’re not going to give up on the diet because you feel too crappy. If that’s going to be the case, then try reducing your carb intake slowly.
Well, we don’t really know why some people feel so bad after this dietary change. Is it related to a detox factor? Is it due to a carb withdrawal? Is there an immunologic reaction? Or is this a result of a change in the gut microbiome? Whatever the reason is, it appears the symptoms attributed to the keto flu may happen, not to everyone but to some people, after “cleaning up” their diet.
It seems strange that a diet that calls for more fat can raise “good” cholesterol and lower “bad” cholesterol, but ketogenic diets are linked to just that. It may be because the lower levels of insulin that result from these diets can stop your body from making more cholesterol. That means you’re less likely to have high blood pressure, hardened arteries, heart failure, and other heart conditions. It's unclear, however; how long these effects last.
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