TCF7L2 and obesity due to melanocortin 4 receptor deficiency: For example, the susceptibility to obesity and T2DM is higher among people carrying genetic mutations of genes such as FTO (fat mass and obesity‐associated gene) or TCF7L2 (transcription factor 7‐like 2) if exposed to a high‐carbohydrate or high‐fat diet (Barrea et al. 2020).