The most recent strategies available for upcycling agri‐food losses and waste (FLW) into functional bioplastics and advanced materials are reviewed and the valorization of food residuals are put in perspective, adding to the water–food–energy nexus. Low value or underutilized biomass, biocolloids, water‐soluble biopolymers, polymerizable monomers, and nutrients are introduced as feasible building blocks for biotechnological conversion into bioplastics. The latter are demonstrated for their incorporation in multifunctional packaging, biomedical devices, sensors, actuators, and energy conversion and storage devices, contributing to the valorization efforts within the future circular bioeconomy. Strategies are introduced to effectively synthesize, deconstruct and reassemble or engineer FLW‐derived monomeric, polymeric, and colloidal building blocks. Multifunctional bioplastics are introduced considering the structural, chemical, physical as well as the accessibility of FLW precursors. Processing techniques are analyzed within the fields of polymer chemistry and physics. The prospects of FLW streams and biomass surplus, considering their availability, interactions with water and thermal stability, are critically discussed in a near‐future scenario that is expected to lead to next‐generation bioplastics and advanced materials. The state‐of‐the‐art strategies to upcycle agri‐food losses and wastes (FLW) into advanced materials are reviewed. The right accent is put on the feasible means of effectively deconstructing and reassembling, synthesizing, or engineering FLW‐derived monomeric, polymeric, and colloidal building blocks targeting multifunctional, sustainable bioplastics. The food–materials–energy nexus is put in perspective as far as the next‐generation bioplastics fitting the circular bioeconomy.