Researchers at Penn State believe that teaching people about eating habits may prove to be an important medical therapy.
They measured the eating competence of 48 people between the ages of 21 and 70, all of whom were at risk of heart disease because of high levels of LDL cholesterol.
The study revealed that participants who were not competent eaters were five times more likely to have high LDL levels.
Commenting on the findings, which are published in the Journal of Nutrition Education and Behaviour, Barbara Lohse, associate professor of nutritional sciences, said: "What we have shown with this research is that we now have an instrument to measure eating competence.
"We are developing a curriculum that we are going to test until we know it instils eating competence," she added.