It is proposed as an eating disorder, or a mental disorder right away. It stems from an apparently good intention, that of eating a balanced diet of healthy food. But when this good purpose becomes obsessive, we have orthorexia.
While anorexia and bulimia are concerned with quantity - too little food or too much - orthorexia is preoccupied about quality. People diagnosed with it are described as "solely concerned with the quality of the food they put in their bodies, refining and restricting their diets according to their personal understanding of which foods are truly 'pure'. The desire to feel pure, healthy and natural leads often to emaciation, as the choice of foods is affected by the perception of the individual about what is pure, healthy and natural. Here is where a sound tendency becomes a disruptive obsession with no exceptions. The quality of life of these persons tend to shrink, despite their effort to achieve the opposite. Their social life is often affected, as they cannot control any of the food served in restaurants and cafés. A 100% strict control on what they eat is the sole condition for them not to feel anxious and possibly "contaminated".