This research explores the remarkable impact of fermented cereals such as sorghum, maize, and wheat with Pediococcus acidilactici WS07, a strain isolated from Ethiopia's traditional borde beverage. The fermented cereal extracts were thoroughly evaluated for antioxidant activity, inhibition of pancreatic lipase and α-glucosidase, metabolite identification through UHPLC-Q-TOF-MS/MS, and in vivo efficacy using the C. elegans model. The results revealed significant enhancements in the bioactive compounds of fermented cereals, demonstrating promising directions for obesity prevention strategies. Notably, the fermented sorghum extracts improved lipase (88.23 %) and α-glucosidase (85.62 %) inhibitory activities compared to its unfermented counterparts. The antioxidant properties of all fermented samples were confirmed through improved DPPH (67.77–71.86 %) and ABTS (59.91–65.49 %) scavenging activities. Fermentation also led to a notable increase in polyphenols and flavonoids, with detailed metabolite analysis revealing a dynamic shift in the composition of these bioactive compounds. Additionally, C. elegans indicates that fermented extracts extend lifespan, reduce lipid accumulation, and lower triglycerides, highlighting their potential as functional foods for health enhancement and obesity management. This study not only underscores the efficacy of P. acidilactici WS07 fermentation in transforming cereals into nutrient-rich functional foods but also provides insight into how microbial fermentation can unlock the health-promoting potential of traditional diets.