When does clean eating become an unhealthy obsession?

Researchers say those who have a history of an eating disorder, obsessive-compulsive traits, dieting, poor body image, and a drive for thinness are more likely to develop a pathological obsession with healthy eating or consuming only healthy food, known as orthorexia nervosa (ON). Although eating healthy is an important part of a healthy lifestyle, for some people this preoccupation with healthy eating can become physically and socially impairing.
Source: Science Daily, https://www.sciencedaily.com