Specific keywords used in this search included “GLP-1, GLP-1R, GLP-1RA, glycogen synthesis, energy metabolism, thermogenesis, liver, pancreas, skeletal muscle, adipose tissue, and BAT.” Other searches were also conducted for foundational and background knowledge for topics such as disease states, treatments, and physiological processes relevant to this review and included terms such as “type 2 diabetes mellitus, obesity, glycogen, glycogenesis, energy balance, metabolism, PASK, TGR5, microbiome, and GLP-1RA”. The gene discussed is GCG; the disease is obesity due to melanocortin 4 receptor deficiency.