Obesity is known as one of the most important health problems around the world. A small portion of the patients die because of a direct result of morbid obesity, but a great deal of degenerative diseases are shortening the life span. The risk of surgical mortality for an obese patient is about two thirds more than a patient in normal weight. It was reported that problems with delayed gastric discharge, delayed wound healing, infections of the injury, sternal dehiscence, atrial fibrillation and respiratory system problems are increasing in obese patients. After all, it is claimed that body size and hospital mortality do not have a relation. The basal energy and protein requirements of the obese patients should be calculated accurately and should not be restricted. It is important to start the nutritional support as soon as possible and to provide glycemie control. It is important to decide oral or enteral nutrition as the first method while starting the nutritional support and if necessary to apply parenteral nutrition.