Ketogenic diet (KD) whilst being an effective method of diet therapy for drug-resistant epilepsy (DRE) is nevertheless accompanied by a significant number of side effects that include the possibility for the delayed physical development in pediatric patients. The problem is multifactorial and is primarily associated with the non-physiological nature of the ketogenic diet itself. Foreign studies on the KD effect on the physical development in children are contradictory and there are none domestic ones. The purpose of this research was to study the dynamics of anthropometric parameters in children with DRE against the background of KD and to assess the possibilities of the alimentary factor in its improvement. Materials and methods used: single-center retrospective cohort study had been carried out on the basis of the Russian Federal Research Centre for Nutrition, Biotechnology and Food Safety (Moscow, Russia) in 2016-2024. The study included patients with an established diagnosis of DRE against the background of KD aged 1 to 18 y/o. Patients were monitored for 24 months as follows: quarterly during the first year and semiannually during the second year of observation, using anthropometric, clinical-laboratory and clinical-instrumental research methods. Results: by the 3rd month of KD, out of 174 pediatric patients, the diet was effective in 105 (60%); by 12th month, 100% control over attacks was achieved in 11 (6%). Analysis of anthropometric parameters made it possible to establish that at the initial point of observation, in accordance with the z-score of the body mass index (BMI), 108 (64%) had normal nutritional status, 22 (13%) had malnutrition and 40 (24%) were overweight/obese. When studying the dynamics of weight and height indicators of children who were on KD throughout the observation period, it was found that the median BMI z-score statistically significantly changed upward (p=0.047), which was largely due to growth retardation, with a decrease in the height/age z-score throughout the observation period (p<0.001). It was found that the protein component of the diet, as well as the level of ketonemia, have a significant impact on the dynamics of the BMI z-score in KD patients. The amount of protein in the diet at 6% to 7% of the energy value contributed to the maintenance of optimal growth parameters in children within this research. Conclusion: the significance of the BMI indicator in assessing the nutritional status over KD decreases against the background of growth retardation. Taking into account the value of the protein/energy indicator when calculating nutrition helps in maintaining of the physical development rate in such patients.