FFAR4 and metabolic disease: The free fatty acid receptors (FFARs), such as FFAR1 (also known as GPR40), FFAR2 (also known as GPR43), FFAR3 (also known as GPR41), and FFAR4 (also known as GPR120), which belong to group A of the G protein-coupled receptor family, have become established as interesting potential therapeutic targets for treating metabolic diseases.