Short chain fatty acids (SCFA) are deceptively simple. There are six of them that are routinely studied (acetate, propionate, butyrate, isovalerate, valerate, and isobutyrate), and they are cheap and relatively straightforward to analyze. Their simplicity belies a much more complex story that is often overlooked. There are many review papers on the subject1–3, but we felt an abridged version was …