In addition, a growing number of epidemiologic studies report differences in the concentrations of leptin, insulin, adiponectin, and ghrelin [[134], [135], [136], [137], [138], [139]], pro-inflammatory cytokines [140], microRNAs, and HMOs [141] in breastmilk as well as changes in metabolomic profiles [134,142] in women with obesity and those affected by type 2 diabetes mellitus (T2DM) and gestational diabetes mellitus (GDM). This evidence concerns the gene LEP and obesity due to melanocortin 4 receptor deficiency.