An obsession can be a bad thing, even if it masquerades as something laudable.

And that is what makes orthorexia nervosa one of the trickiest eating disorders to contend with. In a new study, a team of British and Greek researchers analyzed 16 previous studies that focused on the disorder.

Orthorexia nervosa is an obsession with healthy eating accompanied by restrictive behavior. The attempt to attain perfect health through a pure diet, however, can lead to malnourishment, lost relationships and a sad life.

The person might turn down the office birthday cake every time. Their rigid meal-preparation social media posts are positively reinforced by followers.

And it frequently goes undiagnosed because society, writ large, sees such a diet as virtuous — something we all should be doing. A person with the disorder is continually applauded for the very behavior that is harmful to them.

Imagine you were to try to quit smoking cigarettes, but everywhere you went, people talked about how wonderful it is that you smoke.

The study’s authors say their findings point to a more critical and compassionate approach to health; one that understands the increasingly blurred line between health and disorder, and that resists reinforcing harmful ideals about self-control, food restriction and moralized eating.

Some scholars suggest orthorexia may be a cultural evolution of anorexia nervosa, an obsessive pursuit of thinness that is more widely known. A pursuit of health through clean eating may be more praiseworthy than simply being thin.

Just remember: What looks like self-care on the outside could still be harmful on the inside.