The aim of this study was to examine the impact of introducing a “Tsurun diet,” which is composed of foods classified as 2-1 or lower in the Japanese Society of Dysphagia Rehabilitation classification code and has a higher energy content than conventional dysphagia diets, on achieving full oral intake. The subjects were 64 patients with swallowing disorders who were hospitalized and underwent dysphagia rehabilitation between April 2018 and March 2023. Patients were divided into two groups: those who received a Tsurun diet (Tsurun diet group) and those who received a conventional dysphagia diet (conventional diet group) during swallowing rehabilitation. After propensity score matching to adjust baseline characteristics, the final analysis included 46 patients (19 men, 27 women, mean age 85.8 years). The Tsurun diet group had a significantly higher rate of transition to full oral intake compared to the conventional diet group (73.9% vs. 30.4%, p < 0.01). The Tsurun diet was significantly associated with a higher rate of transition to full oral intake (OR = 13.9, 95% CI 2.45–78.5, p < 0.01). These results show that Tsurun diet intervention was effective in promoting full oral intake.