This guide explains malnutrition as inadequate nutrient intake affecting people with conditions like cancer, COPD, swallowing difficulties, or depression, leading to weight loss, poor immunity, and delayed healing. It provides a simple two-question screening tool for unplanned weight loss and reduced eating, offers dietary strategies including small frequent meals, energy-dense foods, protein-rich options, and nutritional supplements, and emphasizes consulting dietitians for personalized assessment and management when poor appetite or weight loss persists.