PYY and Insulin resistance: Evidence of whether L-Phe reduces food intake; stimulates the release of CCK, PYY, or GLP-1; and is related to insulin resistance seems to vary across species of experiments and levels of L-Phe intake (Zhou et al. 2022; Alamshah et al. 2017; Fitzgerald et al. 2020; Landgraf et al. 1974).