Upcycling for a sustainable food future: turning waste into high-value products for nutrition and health

Upcycling and zero-waste food processing are transforming how we think about leftovers from farms, fisheries, and food production. Instead of letting nutrient-rich coproducts go to waste, new sustainable technologies - such as smart fermentation, green extraction methods, and innovative biotransformation - can turn them into valuable ingredients for healthy foods, supplements, and even animal feed. These materials often contain proteins, fibers, beneficial fats, and health-promoting bioactive compounds. By reclaiming them, we not only reduce landfill use and environmental impact but also strengthen food security, support local economies, and move closer to a truly circular food system. This review highlights sustainable strategies for valorizing agricultural, oilseed, and marine coproducts into high-value functional ingredients and industrial materials, thereby advancing the transition toward a zero-waste, circular bioeconomy.