It is a well-known fact that dysfunction of carbohydrates system, diabetes mellitus inclusive, is highly related with obesity and lack of physical activity.[16] Ninety percent of diabetes mellitus type 2 patients are obese or overweight.[17] We have found that LSG improves glycemic profile, insulin concentration, and HbA1c level, even before significant weight reduction. This evidence concerns the gene INS and obesity due to melanocortin 4 receptor deficiency.