We have previously demonstrated that enhanced aerobic glycolysis and/or autophagy in the tumor stroma supports epithelial cancer cell growth and aggressive behavior, via the secretion of high-energy metabolites. These nutrients include lactate and ketones, as well as chemical building blocks, such as amino acids (glutamine) and nucleotides. Lactate and ketones serve as fuel for cancer cell oxidative metabolism, and building blocks sustain the anabolic needs of rapidly proliferating cancer cells. We have termed these novel concepts the "Reverse Warburg Effect," and the "Autophagic Tumor Stroma Model of Cancer Metabolism.