Each arrow represents a single, independent study showing the respective metabolite to be significantly changed. Upward arrow: upregulated versus control; downward arrow: downregulated. Branched-chain amino acids including valine, leucine, and isoleucine. bAromatic amino acids include phenylalanine, tryptophan, and tyrosine. cSugars include glucose, hexose, mannose, and fructose. dKetone bodies including acetoacetic acid, acetone, and -hydroxybutyric acid. *Median [interquartile range]. BCAA: branched-chain amino acids, FP: fasting plasma, FS: fasting serum, GPC: glycerophosphocholine, NP: nonfasted plasma, NS: nonfasted serum, PtC: phosphatidylcholine, SM: sphingomyelin, #P: plasma with unknown fasting status, #S: serum with unknown fasting status, and ##: unknown sample type with unknown fasting status.