To identify the factors associated with weight loss failure, defined as not reaching the TWL ≥ 20%, a univariate and multivariate analysis comparing the patients with a successful versus non-successful weight loss, including age, initial BMI, T2D, hypertension, dyslipidemia, OSA, depression, smoking and laboratory parameters comprising glucose, hemoglobin A1c, total and HDL cholesterol, triglycerides, insulin and C-Peptide. This evidence concerns the gene INS and type 2 diabetes mellitus.