Malnutrition is a prevalent clinical issue among gastrointestinal cancer patients contributing not only to impaired immune function but also to diminished treatment efficacy delayed rehabilitation and poorer prognosis. The primary causes of malnutrition include tumor - induced metabolic alterations insufficient dietary intake the release of inflammatory mediators and adverse effects associated with radiotherapy and chemotherapy. In recent years psychological distress has emerged as significant contributors to malnutrition warranting greater attention. The process of cancer diagnosis and treatment often triggers profound psychological distress such as anxiety and depression. These psychological stresses may disrupt gastrointestinal function by impairing nutrient intake and absorption. Furthermore tumor-related psychological distress compounded by visceral discomfort arising during treatment frequently induces somatic symptoms such as anorexia fatigue nausea and abdominal distension. Patients may excessively focus on these symptoms exacerbating emotional reactions further reducing food intake and intensifying malnutrition. Current nutritional interventions for cancer patients primarily emphasize the supplementation of specific nutrients with insufficient attention given to the impact of psychological factors. This paper explored the role of psychological distress in cancer - related malnutrition through the lens of psychosomatic medicine. It underscored the necessity of adopting an integrated biopsychosocial medical model in cancer care. Early identification and targeted intervention for psychological and emotional disturbances have the potential to significantly enhance patients' nutritional status improve treatment outcomes and facilitate recovery. This approach provides novel insights and directions for the comprehensive management of cancer patients.