Conventional ecological wisdom holds that nutrients cycle and energy flows in unidirectional chains. However, here, we show that cyclic energy pathways do exist and are common in ecosystems. These important pathways are structurally present primarily due to the contribution of dead organic matter into detrital pools and those organisms that feed on them, reintroducing some of that energy back into the food web. Recognition of these cyclic energy pathways profoundly impacts many aspects of ecology such as trophic levels, control, and the importance of indirect effects. Network analysis, specifically the maximum eigenvalue of the connectance matrix, is used to identify both the presence and strength of these structural cycles.