Genetic mutations, smoking, heavy drinking and negative environmental influences are usually listed as the most common causes of cancer. Now K-State researchers are finding that obesity can be another leading factor. According to the American Institute for Cancer Research, obesity is dangerous because it comes from a lasting energy imbalance, which increases a person's storage of fat and circulating amounts of fatty acids. These higher levels of fatty acids can cause resistance to insulin, a hormone essential to regulating the body's metabolism. Insulin resistance is linked to the development of certain cancers, diabetes and heart disease. George Wang, a K-State associate professor of human nutrition, has been doing research on this topic for several years. According to Wang's research, controlling body weight does affect how a body works at the level of cellular growth, which is important when it comes to researching cancer prevention. The research project, sponsored by the National Institutes of Health, is also being worked on by Richard Baybutt, assistant professor of human nutritionl; Mark Haub, associate professor of human nutrition; and Shie-Shien Yang, professor of statistics. "It is difficult to conduct research like this because when people are obese, they have all kinds of problems," Yang said. "Since they are not healthy, they have a higher chance to get cancer." According to the Web site for the National Cancer Institute, obesity and physical inactivity can account for 25 to 30 percent of several major cancers - colon, breast (postmenopausal), endometrial, kidney and cancer of the esophagus. However, Haub said he is not so sure about the link between weighing too much and developing cancer. "I don't believe being overweight or obese causes much of anything," he said. "It is difficult to state that obesity, at least in humans, causes a disease without taking into account other factors, such as physical activity and diet. I wouldn't say obesity is a cause of cancer, but it is associated with it." Haub conducted research on the effectiveness of exercise for weight management and weight loss. "We found that exercise of reasonable intensity needs to be more than 30 minutes," he said. "Sixty minutes [of exercise] leads to significant differences from a lipid metabolism benefit." Haub said the Midwest population in general and Manhattan residents in particular are more diet-conscious and fitness-conscious than people in other regions of the country. "I think we are in pretty good shape," he said. Haub said he recommended students establish habits of healthy living, like staying away from high-carb, high-fat and low-protein items like candy, chips and french fries, while regularly performing physical activity to stay healthy.