Existing global indices of digital development – the Global Innovation Index (GII), the Network Readiness Index (NRI), and the ICT Development Index (IDI) – measure innovation potential, network readiness, and connectivity coverage, respectively, yet none captures the speed at which economies absorb and convert technologies into economic output. This paper introduces the Technology Metabolism Index (TMI), a parsimonious composite indicator comprising seven openly available sub-indicators from World Bank WDI and UN DESA, structured into three components: Readiness (R), Absorption (A), and Output (O). Grounded in cybernetic feedback-loop theory (Ashby, Beer, Forrester), TMI measures the velocity of technological signal propagation through the R→A→O cycle. A pilot calculation for 10 economies – spanning leaders (Korea, Singapore, Estonia), major economies (USA, EU-5, Japan, China), and developing economies (Uzbekistan, Brazil, Nigeria) – reveals three diagnostic metabolic patterns: "metabolic gap" (Uzbekistan: R >> A >> O ≈ 0), "balanced weakness" (Brazil: R ≈ A > O), and "systemic deficit" (Nigeria: R ≈ A ≈ O ≈ 0). Robustness analysis based on weight differentiation across three scenarios confirms rank stability for all 10 economies without exception. An open-source software implementation (TME_INDEX_CALCULATOR, registered certificate DGU 61047) and a four-sheet Excel model ensure full reproducibility. The TMI fills an unoccupied measurement niche in the global digital monitoring ecosystem and offers policymakers a diagnostic tool with arithmetically verifiable targets for accelerating technology metabolism.