In a recent study performed on the Korean population to determine risk for obesity based on macronutrient intake patterns, Shon et al. [111] found that a very low fat-to-carbohydrate ratio (FC) was linked to a higher risk for obesity than the optimal FC, and this association was in turn modulated by specific polymorphisms of CLOCK, PER2, and CRY1. This evidence concerns the gene PER2 and obesity disorder.