PDK4 and hydrops fetalis: In order to elucidate the mechanism of the observed effects of the HS and HF diets on the PDH flux described above, we measured the amount of total PDH protein, phosphorylated PDH (PDH‐P) as well as the amount of the enzyme known to catalyze this phosphorylation process, the PDH‐kinase‐4 protein (PDK4), by Western blotting as shown in Figures 2A–D and S1.