The SNP entitled 3111 T/C (rs1801260), a substitution of a thymine to cytosine in the 3′-flanking region in the CLOCK gene, was associated with eating behaviors related to late eating and evening types, higher BMI, higher ghrelin, and lower GLP-1 levels, thus influencing the susceptibility to obesity and related diseases such as metabolic syndrome [35,72,73,74,75]. This evidence concerns the gene CLOCK and obesity due to melanocortin 4 receptor deficiency.