Across levels of biological organisation, increases in energy availability often translate into proportionally smaller increases in biomass. For example, in humans and other animals, the phenomenon of energy compensation means that elevated energy intake does not linearly increase stored fat or lean mass, because part of the energy surplus is leaked or diverted into increased expenditure. Strikingly similar patterns occur in ecological communities, where predator biomass typically scales sublinearly with prey biomass, indicating decreasing conversion efficiency at higher resource levels. Here, I investigate whether both patterns can be understood as consequences of shifts in energy allocation under increased resource availability. When energy becomes abundant, organisms that forage efficiently maximise their energetic power (the rate of net energy acquisition) at the cost of reduced conversion efficiency. As a result, proportionally more energy is dissipated rather than incorporated into biomass. To explore this mechanism experimentally, I use a two-species microcosm consisting of a ciliate predator (Euplotes magnicirratus) and its algal prey (Dunaliella tertiolecta). We observe sublinear predator–prey biomass scaling and show that predators increase movement speed when prey is abundant, consistent with optimisation of encounter-driven intake relative to locomotion costs. The additional expenditure reduces the energy available for biomass production, propagating individual-level allocation strategies to community-level carrying capacities. These results demonstrate how individual-level allocation decisions can propagate to population densities and carrying capacities, and suggest a common energetic basis for sublinear biomass production across biological scales.