For many years since I've been starting and managing children on the ketogenic diet, questions like this have come up by parents. What happens years later if my child's cholesterol is high right now? Will they go back to eating normal foods or always like fatty foods? Will they grow more once the diet is stopped? What about their seizures? For years, I'd tell parents that we have contact with many children who are now adults and are doing great years later. One such adult, now 70 years old, was profiled in Keto News 2 years ago. Charlie Abrahams is now an adult and also doing great (http://www.charliefoundation.org/ and click on the third video "Charlie's speech"). However, until this year, we didn't have proof.
In the journal Epilepsia, Dr. Amisha Patel from our ketogenic diet team reported on the long-term effects of the ketogenic diet. This research has made some national attention, including being mentioned in the article last month in the New York Times magazine. As our center's database is now over 17 years old (started in 1993), we felt we had enough long-term follow-up of patients to finally start to answer these questions and more.
Dr. Patel surveyed all children started on the ketogenic diet at Johns Hopkins Hospital from 1993 to 2008 who had not only stopped the diet, but had done so at least 6 months prior. Parents interested in the study could fill out a questionnaire and/or complete lab work. In all, 101 patients ages 2 to 26 years were included and at the time of the follow-up, patients were off the diet anywhere between 8 months and 14 years.
We first looked to see if there were problems years later. None of the patients reported adverse cardiovascular side effects such as heart attacks, enlargement of the heart or abnormal plaque buildup in their arteries. One patient reported having high blood pressure. Two patients later had kidney stones, which is not higher than the average in the population, and no one had abnormal liver or kidney functions with lab testing. Among the 26 who had their cholesterol tested, the average level was 157 mg/dl, with three of the 26 having abnormal levels.
We also found that the common assumption of growth "catch-up" does seem to be true. Nearly all who were now older than 18 years had an average body mass index of 22 (25 and below is considered normal) and most of them were within a few inches of their expected heights, based on their parents' heights. Patients 18 years and younger at the time of the study were, on average, in the 25th percentile for height and in the 36th percentile for weight for their age. While this is below average, the investigators say, it is also much higher than the usual 5th–to-10th percentile while on the diet.
Charlie Abrahams (left) today. About as tall as his brother and taller than his sister!
Interestingly, most of these children still had good seizure control, with nearly 4 of 5 still either seizure-free or >50% seizure reduction from when they had started the diet. This is of course a potential biased sample, as parents who participated in the study may have been more willing in being involved based on a good experience and outcome. However, at least it suggests in these 101 children that seizures don't obviously worsen years later. Researchers have wondered if the diet is "antiepileptogenic" rather than just anticonvulsant, meaning having long-term benefits. This study suggests that may possibly be true.
Carson (www.carsonharrisfoundation.org), now years later and still seizure-free.
Lastly, I was always taught that years after stopping the ketogenic diet, children still would prefer high fat foods and avoid sugary snacks. This study appears to show that is not the case. 92% of children were eating normal foods years later with no obvious food aversions or issues.
Two of our former patients today. Both are clearly fine with eating carbohydrates!!!
Although just the start of studies like this looking at long-term outcomes, this is a good start. As many of these former keto kids become not only young adults (ages 20-30), but even ages 30-50 years in the coming decades, it will be interesting to continue to find out how they are doing. Many parents are worried about the seizures NOW, not problems years later. However, these results may alleviate both concerns.