Long-term impact of the ketogenic diet on growth and resting energy expenditure in children with intractable epilepsy.

Aim: The long-term effects of the ketogenic diet, a high fat diet for treating intractable epilepsy, on resting energy expenditure (REE) are unknown. The aim of this study was to evaluate the impact of 15 months of ketogenic diet treatment on growth and REE in children with intractable epilepsy.

Method: Growth, body composition, and REE were assessed at baseline, 3 months and 15 months in 24 children (14 males, 10 females; mean age 5 y 6 mo [SD 26 mo], range 7 mo-6 y 5 mo), 10 with cerebral palsy [CP]). Fifteen were identified as ketogenic diet responders at 3 months and continued on the ketogenic diet until 15 months. These were compared to 75 healthy children (43 males, 32 females; mean age 6 y 3 mo [SD 21 mo] age range 2-9 y). REE was expressed as percentage predicted, growth as height (HAz) and weight (WAz) z-scores, and body composition as fat and fat free mass (FFM).

Results: HAz declined -0.2 and -0.6 from baseline to 3 months and 15 months respectively (p = 0.001), while WAz was unchanged. In ketogenic diet responders, FFM, age and CP diagnosis predicted REE (overall R(2) = 0.76, p<0.001) and REE did not change. REE adjusted for FFM was lower (p<0.01) in children with CP at baseline (mean [standard error], -143[51] kcals/d) and 15 months (-198[53] kcals/d) compared to the healthy children.

Interpretation: After 15 months of the ketogenic diet, linear growth status declined while weight status and REE were unchanged. REE remained reduced in children with CP.