This study aims to examine the effects of meal delivery services on the nutritional status and mobility of malnourished older adults living alone at a foundation in Taoyuan. Participants will continue their usual diet and consume a daily oral nutrition supplement (ONS) of their preferred type (instant powder with milk or soy milk), provided monthly by social workers for 12 months. Nutritional assessments will be conducted every three months, including the Mini Nutritional Assessment (MNA), anthropometric measures, and 24-hour dietary recall. Mobility will be evaluated using grip strength, walking speed, chair stand test, and calf circumference. Psychological outcomes will be assessed every six months using a quality-of-life questionnaire and the short form of the Geriatric Depression Scale. This study is expected to determine whether regular meal delivery services can improve nutritional status, mobility, quality of life, and depressive symptoms among elderly individuals living alone.