This concept is supposed to induce energetic stress in tumor cells, which in case of malignant brain tumors have frequently been shown to be deficient in key ketolytic enzymes, in particular 3-hydroxybutyrate dehydrogenase 1 (BDH1) and 3-oxoacid-CoA transferase 1 (OXCT1) [8–10], although counterexamples exist [11]. Here, BDH1 is linked to brain neoplasm.