G protein-coupled receptor for medium and long chain saturated and unsaturated fatty acids that plays an important role in glucose homeostasis. Fatty acid binding increases glucose-stimulated insulin secretion, and may also enhance the secretion of glucagon-like peptide 1 (GLP-1). May also play a role in bone homeostasis; receptor signaling activates pathways that inhibit osteoclast differentiation (By similarity). Ligand binding leads to a conformation change that triggers signaling via G proteins that activate phospholipase C, leading to an increase of the intracellular calcium concentration. Seems to act through a G(q) and G(i)-mediated pathway. Mediates the anti-inflammatory effects of omega-3 polyunsaturated fatty acids (PUFAs) via inhibition of NLRP3 inflammasome activation. {ECO:0000250|UniProtKB:Q76JU9, ECO:0000269|PubMed:12496284, ECO:0000269|PubMed:17699519, ECO:0000269|PubMed:23809162, ECO:0000269|PubMed:24130766, ECO:0000269|PubMed:24742677}. This is the function of FFAR1 (free fatty acid receptor 1, ENSG00000126266).