Even something as good for you as a commitment to healthy eating can become an unhealthy obsession, some experts are saying.

Orthorexia – a fixation on maintaining a perfect diet – is a term coined by Steve Bratman, M.D. in a 1997 essay for Yoga Journal; he subsequently elaborated on the concept in his 2001 book, HealthFood Junkies.

People who are obsessed with eating healthy may avoid factory-farmed meats, hormone-laden dairy, non-organic fruits and vegetables, anything hydrogenated or microwaved. Artificial ingredients, MSG, bleached products such as white rice, bread and sugar may all end up on the no-no list.

The eating disorder combines elements of more well-known disorders such as anorexia and obsessive-compulsive disorder. Orthorexia becomes unhealthy when it causes distress and interferes with everyday life. That is, when fear of unhealthy food prevents a person from eating out with friends or attending dinner parties, it’s gone too far. Some say it can lead to malnourishment, anorexia or disabling anxiety.

“I was terrified of food that didn’t fit within my idea of what was healthy,” says Nisha Moodley, a 32-year-old health coach in New York City. “I was terrified of cancer, of dying.”

But it’s not an official diagnosis: Orthorexia is not recognized by the American Psychiatric Association and there are no plans to add it to the APA’s Diagnostic and Statistical Manual of Mental Disorders (DSM), a new edition of which is due out in 2013.

What makes it an especially pernicious disorder is that people obsessed with eating healthy often are rewarded with positive feedback for the behavior. .

“One of the things that’s tricky about our culture is that orthorexia is socially acceptable and often even heralded as a great statement of self-control and doing the right thing for your health,” says Amanda Mellowspring, a registered dietician in Miami who specializes in eating disorders.