As people become more educated, studies have demonstrated that they tend to choose foods that are lower in calories but higher in nutrients. They also pay more. In a study published in the May 2009 issue of the Journal of the American Dietetic Association, researchers from the University of Washington compared the eating habits and food costs of a sample of 164 adults in the Seattle, Washington area. Diets of low energy density and high nutrient content have been associated with less weight gain and with lower rates of obesity, type 2 diabetes, cardiovascular disease and some forms of cancer.