Despite the efficacy of KD in patients with epilepsy and certain metabolic diseases, such as GLUT1 deficiency [28] and PDHC deficiency [22,29,30,31], many patients find it very difficult to persist with a prolonged restrictive diet like the ketogenic diet, especially when the treatment is for life [32]. This evidence concerns the gene SLC2A1 and hyperinsulinemic hypoglycemia, familial, 4.