introduce the concept of Vacuum Metabolism, a theoretical framework suggesting that living systems could, in principle, harness the quantum vacuum as an additional source of usable energy. Traditional bioenergetics describes cellular function as entirely dependent on biochemical processes such as oxidative phosphorylation and glycolysis, where nutrients are oxidized to generate adenosine triphosphate (ATP). However, the omnipresence of vacuum fluctuations at all spatial and temporal scales raises the provocative possibility that biology might have evolved, or could be engineered, to partially exploit this invisible energetic reservoir. This paper develops the conceptual foundations of such a framework. It examines possible mechanisms by which nanoscale biological structures — such as ion channels, protein cavities, and membrane resonators — might modulate or couple to zero-point electromagnetic fields. Analogies are drawn with established physical phenomena including Casimir-type effects, cavity quantum electrodynamics (QED), and coherence in quantum biology. Building upon these analogies, a minimal energetic model is introduced, in which a vacuum-derived contribution is added to the classical free energy balance of the cell. Several falsifiable predictions are proposed. If Vacuum Metabolism is plausible, measurable anomalies could emerge in vibrational spectra, ion transport kinetics, or photon emission statistics under controlled laboratory conditions. Potential experimental strategies include the design of biomimetic nanocavities to mimic protein environments, the monitoring of ion channel dynamics in altered vacuum-field conditions, and the use of ultrasensitive spectroscopies to detect shifts in vibrational states correlated with zero-point field modulation. This pioneering work establishes a testable foundation for integrating vacuum field phenomena into bioenergetics. Beyond its theoretical implications, it opens a novel paradigm in biology, with potential applications in regenerative medicine, space exploration, biotechnology, and the development of bio-inspired quantum energy devices. By introducing this framework, I aim to stimulate rigorous debate and experimental inquiry into the possible role of the quantum vacuum as a biological energy source — a prospect that could reshape our understanding of life and energy at the most fundamental level.