Factors Associated With Growth in Patients Treated With the Classic Ketogenic Diet for Drug-Resistant Epilepsy

Suboptimal growth and malnutrition are often cited as complications of ketogenic diet therapy in patients with drug-resistant epilepsy; however, there is conflicting evidence on the factors that contribute to growth.

This is an observational, case-based study to evaluate growth in patients with drug-resistant epilepsy treated with the classic ketogenic diet for at least 12 months. Age, gender, height, weight, and body mass index (BMI) were collected at baseline and epilepsy clinic standard-of-care visits (one month, six months, and 12 months after diet initiation). Dietary intake and laboratory measures including glucose, bicarbonate, and beta-hydroxybutyrate were also collected.

119 patients were included. After ketogenic diet initiation, there was a significant fall in height z score from baseline to 12 months (-0.15, P = 0.001) but no other significant changes in weight, weight-for-length/BMI, or height z scores were noted between any time points within the 12 months after diet initiation. When separated by age, height z score changes were limited to those aged zero to three years. This was accompanied by a significant decrease in energy intake 12 months after treatment in this age group. When separated by diet route, weight z scores at each time point were significantly lower in the group eating by mouth than tube.

Our study provides further evidence that the classic ketogenic diet impacts growth. Our population demonstrated restriction in linear growth in those aged zero to three years, which correlated with declines in energy intake, and weight declines limited to patients fed by mouth.