Chronic weight loss results from a combination of factors including chronic decreased nutrient intake, poor nutrient utilization or malabsorption, and increased metabolic requirements The differential diagnosis of chronic weight loss is very broad, and can include serious underlying diseases such as malignancy, congenital heart disease, and chronic lung disease Psychosocial factors such as abuse, neglect, lack of food availability, and incorrect formula or food preparation are often important factors Developmental delay and feeding disorders also often contribute to inadequate intake of nutrients Often, the etiology of chronic weight loss is multifactorial and complex A complete history, physical examination, and review of systems are necessary to identify the underlying causes of chronic weight loss, and often a specific diagnosis may not be identified in the emergency department