Orthorexia, also known as Orthorexia nervosa, is a medically unrecognized mental disorder characterized by an extreme aversion to foods perceived to be unhealthful, whether those foods actually are unhealthful or not. Rather than merely reducing the quantity of questionable food consumed, a typical orthorexic will lump broad categories of food together as "bad for you" and avoid all of them entirely.
This might include avoiding foods that aren't organic, or aren't vegan, or are vegan, or are cooked, or are acidic, or are fruit, or aren't fruit, or have too much yang, or contain even the slightest trace of high fructose corn syrup or trans fat or gluten, or that someone might be allergic to despite a lack of obvious symptoms.
The condition can be exacerbated by visiting a nutritionist.
The OED's first citation for use of the term is a 1997 article in the Yoga Journal (Sept.–Oct. 44) where the writer claims to have coined the term "orthorexia nervosa" by analogy with "anorexia nervosa".
 See also
- Orthorexia Nervosa on nationaleatingdisorders.org
- The Terrible Tragedy of the Healthy Eater
- Why it’s so easy to believe our food is toxic, on PLOS blogs
- Orthorexia: When healthy diets go too far, San Jose Mercury News, 27-Aug-2014
- Orthorexia, Also Nicknamed the Food Babe Disorder, This Week in Pseudoscience, 7-Sept-2014
- When Healthy Eating Calls For Treatment, Wall Street Journal, 10-Nov-2013
- When an Obsession With Healthy Eating Becomes a Dangerous Risk, ABC News, 13-Nov-2014
- Orthorexia: When clean eating spirals out of control, well&good, stuff.co.nz, 12-Nov-2015