Some authors justify the use of ketogenic diet for the treatment of obesity based on the carbohydrate-insulin model, that theorize that diets high in carbohydrates induce: (1) hyperinsulinemia and decreased adipose tissue lipolysis, thereby reducing fatty acid release [400]; (2) fat storage in the adipose tissue and decreased plasma glucose levels; (3) decreased oxidation of fatty acids in metabolically active tissues, such as heart, muscle, and liver; (4) increased calorie intake and obesity [400–403]. Here, INS is linked to obesity due to melanocortin 4 receptor deficiency.