A study with an intent-to-treat prospective design was published in 1998 by a team from the Johns Hopkins Hospital[19] and followed-up by a report published in 2001.[20] As with most studies of the ketogenic diet, there was no control group (patients who did not receive the treatment). 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 twelve 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.[20][21]
When you’re eating the foods that get you there (more on that in a minute), your body can enter a state of ketosis in one to three days, she adds. During the diet, the majority of calories you consume come from fat, with a little protein and very little carbohydrates. Ketosis also happens if you eat a very low-calorie diet — think doctor-supervised, only when medically recommended diets of 600 to 800 total calories.