Nutritional management plays an important role in medical care. The number of nutrition support team （NST） has been rapidly increased in Japan since ２０００. Recently, many medical workers, such as doctor, nurse, pharmacist, and dietitian, are interested in nutritional management and nutrition therapy. For instance, sarcopenic obesity and weight loss in cancer patients are attracting attention. Sarcopenic obesity is defined by the combination of obesity and low muscle mass. This condition is closely related to functional decline and mortality. Sarcopenic obesity is not able to be diagnosed by body weight or body mass index, suggesting that body composition should be also considered. Weight loss is common among patients with cancer. About ５０％ of patients with cancer report unexplained weight loss at the time of diagnosis, and up to ８０％ of patients with advanced cancer experience weight loss and cachexia. The weight loss is divided into two types, which are Cancer-Associated Weight Loss （CAWL） and Cancer-Induced Weight Loss （CIWL）. Nutritional management and nutrition therapy for weight loss in cancer patients are different between these two types.