Orthorexia

Excessive concern with consuming a diet considered to be correct in some respect, often involving the elimination of foods or food groups supposed to be harmful to health.
A disorder characterized by a morbid obsession with eating only healthy foods.

The OED reports the first use to be as recent as 1997, viz.:

“Orthorexia nervosa refers to a pathological fixation on eating proper food.”
[Yoga Journal; September-October 1997]

“Orthorexia – like anorexia and bulimia – eventually reaches a point where it takes over the sufferer’s life … Raw food fans take this to the utmost extreme.”
[Cosmopolitan (UK edition); September 1998]