Under the multivariate logistic regression model adjusted for age and sex, no significant association was found between the MTHFR C677T polymorphism and being overweight/obesity when examining homozygous codominant (odds ratio (OR) = 1.06, 95% confidence interval (CI) = 0.75–1.51, p = 0.738), heterozygous codominant (OR = 0.83, 95% CI = 0.59–1.08, p = 0.308), dominant (OR = 0.92, 95% CI = 0.65–1.32, p = 0.655), recessive (OR = 1.21, 95% CI = 0.88–1.67, p = 0.245) and allelic (OR = 1.05, 95% CI = 0.85–1.30, p = 0.626) models (Table 2). Here, MTHFR is linked to obesity due to melanocortin 4 receptor deficiency.