In this first analysis of DNA methylation of the ADRB3 gene in a population-based study, the most relevant results obtained were the high prevalence and association between ADRB3 DNA hypermethylation with overweight and obesity in both genders, a higher waist–hip ratio for men, higher trans-fat intake, an altered lipid profile, and decreased folic acid intake. This evidence concerns the gene ADRB3 and Obesity.