Obesity triggers many health problems, especially diabetes and atherosclerosis, or complicates treatment of these diseases. Increased body weight and body fat ratio are characterized by endocrine, metabolic and immunological changes and are associated with many chronic diseases. Various types of cancer are also associated with these diseases. The association of obesity with cancer is less known than with diabetes and cardiovascular effects. However, scientific data supports that increase of fat rate in the body may increase the incidence or cancer-related mortality rates in some types of cancer. These cancer types include colon, esophagus, gastric cardia, rectum, gall bladder, pancreas, kidney, over, endometrium, and postmenopausal breast cancers. In the literature, it has been shown that every 5 kg/m2 increase in body mass index leads to a 30% increase in any causal mortality and 10% increase in mortality due to cancer. For this reason, the protection of healthy body weight plays an important role especially in the prevention of these cancer types. If efforts in order to prevent obesity increase, the incidence of cancer will be reduced with the provision of weight control.