FFAR4 and obesity due to melanocortin 4 receptor deficiency: This discrepancy between studies may possibly be explained by the difference in HFDs utilized to invoke HFD-induced obesity as other studies showing upregulation of adipose tissue GPR120 gene expression in obese mice have utilized diets composed of considerably more fat (60% of total calories from fat) and long-chain FAs, which serve as natural ligands of GPR120 [29].