Former food products (FFPs) are increasingly recognized as sustainable feed ingredients. While nutritionally valuable, FFPs may contain cocoa-based confectionery, which is a source of methylxanthines such as theobromine (TB) and caffeine (CF) and can impact animal health. This study quantified TB and CF concentrations in 12 FFPs using HPLC-UV, evaluated FFP inclusion rates in animals’ diets against European Union (EU) maximum levels (MLs), and dietary exposure against toxicological thresholds. TB levels ranged from 59.6 to 1147.1 μg/g and CF from 9.3 to 118.1 μg/g. All products, except one, complied with EU MLs when included at 30% in the diet (on a dry basis). Modeled animal dietary exposure (ADE) indicated that, in most proposed species, TB intake was below safety thresholds; however, the maximum exposure scenarios in piglets exceeded reported no-observed adverse effect levels (NOAEL). These findings highlight the need for species-specific and production-stage-specific evaluations and accurate quantification of methylxanthines when formulating diets with FFPs