Multifunctional regulator of fatty acid metabolism. Represses transcription of at least eight genes required for fatty acid transport and beta-oxidation including fadA, fadB, fadD, fadL and fadE. Activates transcription of at least three genes required for unsaturated fatty acid biosynthesis: fabA, fabB and iclR, the gene encoding the transcriptional regulator of the aceBAK operon encoding the glyoxylate shunt enzymes. Binding of FadR is specifically inhibited by long chain fatty acyl-CoA compounds (By similarity). Homodimer.