The South American canid genus Lycalopex comprises six species morphologically similar but inhabiting diverse environments. Although their diets have been studied locally, a comprehensive synthesis is lacking. We conducted a systematic literature review (Web of Science, Scopus, Google Scholar) to compile published trophic data, resulting in 83 studies. Lycalopex culpaeus was the most studied species, and Chile had the highest research output; however, rarefaction analyses confirmed this distribution reflects a significant sampling bias among species and countries. Mammals, particularly rodents, were the primary prey across the genus. We found notable trophic niche variation: L. culpaeus and L. gymnocercus displayed the greatest trophic breadth (generalists), whereas L. griseus was more specialized. A stronger tendency towards carnivory was observed in L. fulvipes, and towards herbivory in L. sechurae. Crucially, these latter two species were the least studied, with minimal sampling effort (<600 hours across only two sites), suggesting their current dietary profiles may be unrepresentative. This work provides the first integrative analysis of Lycalopex trophic ecology. Our findings not only reveal key dietary patterns but, more importantly, highlight critical taxonomic and geographic research biases, offering a data-driven framework to prioritize future studies on the understudied L. fulvipes and L. sechurae to inform their conservation.