From Wikipedia: "Orthorexia nervosa (also known as orthorexia) is a proposed eating disorder or mental disorder characterized by an extreme or excessive preoccupation with avoiding foods perceived to be unhealthful. The term orthorexia derives from the Greek ορθο-(ortho, "right" or "correct"), and όρεξις (orexis, "appetite"), literally meaning a correct diet. It was introduced in 1997 by Steven Bratman, M.D., to be used as a parallel with other eating disorders, such as anorexia nervosa. Orthorexia is not mentioned in the widely-used DSM, but was coined by Bratman who claims that in rare cases, this focus may turn into a fixation so extreme that it can lead to severe malnutrition or even death. Even in less severe cases, the attempt to follow a diet that cannot provide adequate nourishment is said to lower self-esteem as the orthorexics blame themselves rather than their diets for their constant hunger and the resulting cravings for forbidden foods.
"Sufferers of orthorexia often display symptoms consistent with obsessive-compulsive disorder and have an exaggerated concern with healthy eating patterns." Read more: Orthorexia nervosa