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). MCTs are more efficiently absorbed and are rapidly transported to the liver via the hepatic portal system rather than the lymphatic system. 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. The MCT diet replaced the classic ketogenic diet in many hospitals, though some devised diets that were a combination of the two.
A Cochrane systematic review in 2018 found and analysed eleven randomized controlled trials of ketogenic diet in people with epilepsy for whom drugs failed to control their seizures. Six of the trials compared a group assigned to a ketogenic diet with a group not assigned to one. The other trials compared types of diets or ways of introducing them to make them more tolerable. In the largest trial of the ketogenic diet with a non-diet control, nearly 38% of the children and young people had half or fewer seizures with the diet compared 6% with the group not assigned to the diet. Two large trials of the Modified Atkins Diet compared to a non-diet control had similar results, with over 50% of children having half or fewer seizures with the diet compared to around 10% in the control group.
But people who started following the keto diet noticed weight loss for a few reasons: When you eat carbs, your body retains fluid in order to store carbs for energy (you know, in case it needs it). But when you’re not having much in the carb department, you lose this water weight, says Warren. Also, it's easy to go overboard on carbohydrates—but if you're loading up on fat, it may help curb cravings since it keeps you satisfied.
A study with an intent-to-treat prospective design was published in 1998 by a team from the Johns Hopkins Hospital and followed-up by a report published in 2001. 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.
Another difference between older and newer studies is that the type of patients treated with the ketogenic diet has changed over time. When first developed and used, the ketogenic diet was not a treatment of last resort; in contrast, the children in modern studies have already tried and failed a number of anticonvulsant drugs, so may be assumed to have more difficult-to-treat epilepsy. Early and modern studies also differ because the treatment protocol has changed. In older protocols, the diet was initiated with a prolonged fast, designed to lose 5–10% body weight, and heavily restricted the calorie intake. Concerns over child health and growth led to a relaxation of the diet's restrictions. Fluid restriction was once a feature of the diet, but this led to increased risk of constipation and kidney stones, and is no longer considered beneficial.
Epilepsy is one of the most common neurological disorders after stroke, and affects around 50 million people worldwide. It is diagnosed in a person having recurrent, unprovoked seizures. These occur when cortical neurons fire excessively, hypersynchronously, or both, leading to temporary disruption of normal brain function. This might affect, for example, the muscles, the senses, consciousness, or a combination. A seizure can be focal (confined to one part of the brain) or generalised (spread widely throughout the brain and leading to a loss of consciousness). Epilepsy can occur for a variety of reasons; some forms have been classified into epileptic syndromes, most of which begin in childhood. Epilepsy is considered refractory (not yielding to treatment) when two or three anticonvulsant drugs have failed to control it. About 60% of patients achieve control of their epilepsy with the first drug they use, whereas around 30% do not achieve control with drugs. When drugs fail, other options include epilepsy surgery, vagus nerve stimulation, and the ketogenic diet.
Variations on the Johns Hopkins protocol are common. The initiation can be performed using outpatient clinics rather than requiring a stay in hospital. Often, no initial fast is used (fasting increases the risk of acidosis, hypoglycaemia, and weight loss). Rather than increasing meal sizes over the three-day initiation, some institutions maintain meal size, but alter the ketogenic ratio from 2:1 to 4:1.
As per heartburn, studies done have shown that a ketogenic diet can have beneficial effects for those who have Non Alcoholic Fatty Liver Disease. A 2006 paper published in the Journal of Digestive Diseases and Sciences found that ‘Six months of a low-carbohydrate, ketogenic diet led to significant weight loss and histologic improvement of fatty liver disease’
As mentioned, there are a few reasons why the keto diet usually equals weight-loss gold, says Keatley. For starters, people usually reduce their daily caloric intake to about 1,500 calories a day because healthy fats and lean proteins make you feel fuller sooner—and for a longer period of time. And then there’s the fact that it takes more energy to process and burn fat and protein than carbs, so you're burning slightly more calories than you did before. Over time, this can lead to weight loss.