Nutrition impact symptoms (NIS) involve any barrier to a patient’s nutritional status. Cancer and its treatments often lead to complex side effects that develop rapidly and change in character and intensity throughout treatment. Barriers to eating and drinking, digesting, and absorbing nutrients lead to negative clinical outcomes for patients with cancer, including malnutrition. Prompt assessment and interventions are key to helping patients avoid treatment holidays and dose reductions while also promoting the best possible quality of life during their cancer journey. In fact, a weight loss of just 5% is an indicator that a patient will likely not receive all of his or her prescribed cancer treatment.