I don't think the name should even end in "exia." I don't get why caring about your health is a problem, and I would argue that any really intelligent, intellectual, passionate person approaches problem solving (ie: What should I eat) with intensity and focus. And after all, what we eat is no small thing! We eat three to five times every single day! It is a HUGE part of life!
Many of the scientists who made seminal discoveries were obsessed with their work. Does that qualify as a disease?
Imagine if 80% of the world was orthorexic? Imagine the positive change.
Orthorexia is a problem when it causes you anxiety and makes your life miserable.
When I lived in the San Francisco Bay Area and was a member of the raw vegan community I would occasionally attend community potlucks. I noticed that those people were among the most neurotic people I had ever met and many looked quite unhealthy for all the bragging they did about their way of eating. It's one thing to care about your diet, to read everything you can about it, to eat as healthy as you can but when diet becomes the center of your life to the point where you isolate from others, or live in fear of going out to dinner because that piece of fish might have been farmed, or spend your energy judging others to the point of being miserable, or get sick from your diet and think that means you have to blindly follow it even more strictly, then I think it's a problem.
I've been there, done that. I've relaxed A LOT since my days of crazy food obsession. Now, I'm only moderately obsessive about food and I make it a point when I'm with family or friends at their homes or at a restaurant to enjoy what's available even if it's, gasp, glutenous.
Of course I realize that some folks here have real problems with gluten, casein, and other things, and get sick when they eat those things. I'm not saying those people are orthorexic or that they have a problem.
It's not so much what you eat or how much you analyze your food that makes you or me orthorexic. It's when diet consumes you and other important elements of your life (mental, emotional, spiritual, family. relationships) are ignored. I work hard to keep non-food areas in balance because I believe that in my case they're more important to my life than what I eat.
I do think that PaleoHacks attracts those of us who are at risk for being orthorexic because the culture of this community is that it largely treats food as if it's the one thing to pay attention to. Unfortunately, it also encourages those of us who are out of balance already in relationship to food to continue to stay out of balance.
CrowLover, I believe Orthorexia nervosa is orthorexia.
Chinaeskimo, Orthorexia is a mental disorder according to Wikipedia. I am kind of hard core about certain foods not entering my body, sometimes more hardcore than at other times, but that is very different from orthorexia. An example might be a vegan who has had their blood tested and even though they are told they're severely deficient in essential vitamins and are sick because of it they continue eating the way they 'believe' is healthy. It may sound straight up 'stupid' but it's not. It's a mental illness, not just an extreme commitment to healthy eating.
From Wikipedia: Orthorexia nervosa (also known as orthorexia) is not mentioned in the DSM[a] first used by Steven Bratman to characterize people who develop an obsession with avoiding foods perceived to be unhealthy. Orthorexia nervosa is believed to be a mental disorder. Bratman 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. 
Imagine a scenario where, for the rest of your life, all you have to eat are Cheetos, Twinkies, and Coke. The problem with orthorexia is when you'd rather starve than eat any of those (this is an extreme case).
Other than that, it is okay to want to eat as healthy as possible. But it is important to be rational and accept the fact that eating some "unhealthy" food is inevitable.
What is the definition of orthorexia? 3 Answers