Studies focusing on the diet of insectivorous bats enhances our understanding of species foraging ecology, and the various ecosystem services provided by bats (especially regulating and suppressing pest populations). This service provides an important insight on their roles in ecosystems, and decreases crop damage as well as increasing productivity, reducing pesticide application, and as significant source of energy for cave ecosystems. This study aimed to understand patterns and provide an overview of how bat diet research has changed over seven decades, to enable more effective future research on conservation and bat pest-control related services. In this study, we reviewed and synthesized the insectivorous bat diet literature and the research which reported the dietary composition that published between 1950 and 2020 to evaluate trends and changes in research. We found studies on 374 species (33.3% of insectivorous species), and a progressive increase in research during over seven decades across all nine regions. The majority of publications were concentrated in North America (116 publications) with fewer studies in countries from the tropics. Most studies took place in natural areas (252 studies) with fewer in buildings and agroecosystems. All insectivorous-bats families were included in diet research, with Vespertilionidae having the greatest coverage (275 studies). Our synthesis highlights clear spatial and taxonomic biases in research. Future studies should focus on all and include more research in agroecosystems and urban areas to understand their roles in ecosystems as well as promote bat conservation.