For the cancer subjects, the study involves 1 test day prior to a chemotherapy treatment, a 10-week (± 2 weeks) nutritional intervention period at home starting the first day of the chemotherapy treatment, and one test day after this intervention. Chemotherapy in general lasts at least a few months. Recent studies indicate that a 10-week nutritional supplementation period should be long enough to reach significant improvements in nutritional and clinical outcome parameters during chemotherapy. Throughout these 10 weeks the cancer subjects will take the supplements at home. Cancer subjects will be randomly assigned to receive either fish oil or a placebo and protein or a placebo and will take these supplements daily throughout 10 weeks during chemotherapy.