Adopting sustainable food choices is crucial to mitigating the environmental impacts of food production. Insect-based foods offer a promising alternative with low resource requirements and reduced greenhouse gas emissions. This study examines the psychological factors influencing consumers’ intentions to purchase insect-based foods using an extended protection motivation theory (PMT) model that includes disgust as a critical factor. Data from 233 Italian participants were analyzed through partial least squares structural equation modeling (PLS-SEM). Results indicate that perceived response efficacy—the belief in the environmental benefits of insect consumption—and self-efficacy—confidence in one’s ability to incorporate insect-based foods—positively influence purchase intentions. However, strong aversions rooted in disgust and low intrinsic motivation present major barriers, highlighting cultural resistance to entomophagy in Western contexts. Extrinsic motivators such as social recognition, perceived costs, and perceived severity or vulnerability to environmental issues had no significant effect. The findings suggest that effective strategies should focus on reducing disgust and strengthening consumer confidence, emphasizing the environmental benefits to shift attitudes toward sustainable dietary choices.