Percentage total weight loss was correlated to improvement in insulin levels in patients of all subgroups, without diabetes (Spearman rank correlation coefficient, r = − 0.213, p < 0.001), prediabetics (r = − 0.424, p < 0.001), as well as diabetics (r = − 0.505, p < 0.001). Here, INS is linked to diabetes mellitus.