Patients with cancer or with a history of cancer often seek nutritional advice. In turn, cancer health care providers are often asked questions related to nutrition and cancer. Should I take high-dose vitamins or other high-dose supplements? Should I take a regular-dose vitamin or other regular-dose nutritional supplements? Will I experience weight loss during postoperative chemotherapy? What should be my weight goals during and after adjuvant therapy? In the setting of advanced cancer, what should I do to keep my appetite and weight up? This review attempts to provide data-driven answers to some of these commonly posed questions.