This was an observational study of hospitalized patients with dementia who developed COVID-19. The disease course, dietary intake, and disease severity (mild/severe) were evaluated. Twenty-nine patients with a median age of 84 years, with both mild (18) and severe conditions, (11) were evaluated. Mild group had decreased food intake from the day of symptom onset. In the severe group, the decline began the day before symptom onset. On day 30 of the disease, the median food intake of the mild group returned to levels observed prior to symptom onset, in contrast to those in the severe group.