Studies on a variety of interesting biological problems, ranging from circadian rhythm to cancer cell growth to longevity, have begun to give evidence that the physiological state of cells and tissues reflects both the cell's regulatory systems and its state of intermediary metabolism. It is appreciated that the regulatory state of a cell or tissue, as driven by transcription factors and signaling pathways, can impose itself upon the dynamics of metabolic state. It follows that the reciprocal must also be the case, that metabolic state will feed back to impose itself on regulatory state. An appreciation and understanding of this reciprocity may be required to crack open problems in biological research that have heretofore been insoluble.