Patients with head and neck cancer often have distinct nutrition needs. The unique set of side effects of the disease process and treatment cause the patient to develop nutritional challenges. The challenges are complex to manage, often requiring supplemental feedings. Proper calculation of protein and caloric intake is necessary to meet the increased needs. Taking treatment and activity levels into account also is necessary when calculating nutrition requirements. Fluid balance can be delicate and requires attention, too. The dietitian determines the fluid needs of patients, using one of several calculations, and need is based on the patients' laboratory work and overall hydration status, which can be affected by inadequate fluid intake, diarrhea, and vomiting.