I only came across any mention of the condition Orthorexia Nervosa very recently and it interested me enough to take another look.
The condition was identified by Steven Bratman who also named and defined it and wrote a book about it called 'Health Food Junkies.
' In common with Anorexia and Bulimina Nervosa it's an eating disorder.
However, the focus of the disorder is around taking healthy eating to the point of obsession.
This can happen by following particular diets such as raw foodism, macrobiotics and the blood type diet advocated to be health giving to the point that any food not included in the diet is religiously avoided.
Symptoms of Orthorexia Nervosa

• feeling superior to others because you are following your diet strictly
• spending so much time buying preparing and eating food that other activities are crowded out
• social isolation because of the difficulty of eating with others, eating out etc.
  
• eating very little and getting underweight because of the fear of eating food that isn't allowed

Like other eating disorders psychological reasons are what starts of the condition which can include a desire for slimness but are more likely to be about other concerns such as food safety and the pursuit of health.
I have to put my hand up and say I haven't read the book yet, so I'm not in a position to review the book.
However, even just reading about it stirred up a number of feelings for me.
My immediate thoughts were that I could identify very strongly with with the symptoms at certain times of my life when having tried conventional approaches to getting rid of unwanted conditions and getting nowhere I was willing to try extreme diets if they offered me some relief.
I also have some agreement with the point of view that this is knocking people who want to eat healthily and just because they don't want to eat 'normal' food which is mostly polluted or junk must be labelled by a special name to make those who are less discerning feel better about their diets.
But I think that the point that this makes to me and the conclusion I'd already come to for myself is that we live in the world we live in.
Whilst living a healthy life, including eating wholesome, natural food as much as possible should be a priority for us all, allowing it to become an obsession can be more harmful than a less than perfect diet.