The natural decline in bodily functions associated with aging can lead to difficulties in chewing and swallowing, which may result in various health problems, including muscle weakness and nutritional deficiencies. Accordingly, controlling food texture and viscosity has become a widely used strategy for managing swallowing difficulties. In this study, we developed an age-friendly rice flour–based soft food supplemented with mealworm powder, a sustainable and high-protein food source. Soft food samples formulated by varying the content of size-controlled mealworm powder were analyzed using rheological measurements to evaluate their viscoelastic behavior. The measured rheological properties were compared with the criteria specified in dysphagia diet standardization guidelines. This approach enables effective control of food texture and viscoelasticity, thereby facilitating the development of softened foods that meet the nutritional needs and preferences of older adults with dysphagia.