It's safe to say that consuming most your calories, macronutrients, and micronutrients from minimally processed foods is optimal, logical, and reasonable. In practice this approach can easily be taken to the extreme.
Related: Death to Cheat Meals, Clean Eating and Pleasure Deprivation
Orthorexia nervosa is an eating disorder characterized by an unhealthy obsession with food quality and purity.  Although not officially recognized by the medical community the American doctor Steven Bratman began using this term nearly 20 years ago. 
Those suffering from orthorexia have intense feelings towards certain foods and ingredients. For example, they may label canned and conserved products as dangerous, fresh produce as healthy, and manufactured products as artificial. 
Ironically, such practices designed to improve health can have severe negative health and social consequences. This article explores the causes, symptoms, and impact of orthorexia.
Orthorexia Nervosa CausesIn most cases individuals begin their fitness journey with the desire to improve health and body composition through making healthier foods choices. As an individual begins experiencing positive physical, mental, and emotional changes, he or she may attribute the results to adhering to one of the following dietary rituals:
- Chronic consumption of specific foods or ingredients.
- Elimination of specific foods or ingredients.
- Consumption of meals at specific times each day.
- Time at which the food or meal is consumed.
- Use of specific methods and utensils to prepare the food.
Regardless, those at an increased risk for developing orthorexia include women, adolescents, and participants in image-based physical activities like bodybuilding, gymnastics, and dancing.  Researchers are unable to pinpoint the exact cause of orthorexia but believe the following personal traits and characteristics may significantly increase the likelihood of developing the condition:
- Restrict food choices for health reasons rather than due to social or peer pressure. 
- Exhibit a combination of obsessive-compulsive personality traits and exaggerated eating behavior patterns. 
- Make food choices to improve the perception of safety through disease prevention. 
- Exhibit exceptionally careful, detailed, and tidy tendencies but also an exaggerated need for selfcare and protection. 
- Currently have or overcame bulimia nervosa or anorexia nervosa. 
- Exhibit the compulsion for complete control, a desire to escape from fears, and/or a yearning to be thin. 
- Believe that food choices are the most direct way to improve societal standing, build an identity, search for spirituality, and demonstrate self-deprivation. 
- Recently underwent dramatic changes in weight over a short period and/or perceive being overweight as a sign of weakness. 
Orthorexia Nervosa SymptomsOrthorexia can manifest itself through a number symptoms that thankfully don't require expensive blood tests or multiple visits to the doctor. However, it is important to note that the intensity and frequency of these symptoms plays a significant role of diagnosing the eating disorder.
Just because you, your family member, or loved one exhibits one or two of the symptoms once in a blue moon during the fitness journey, one should not automatically assume the development of orthorexia.
Food elimination and avoidance is by-far the most common symptom associated with orthorexia. Common avoidances include are foods with artificial colors, artificial flavors, preserving agents, pesticide residues, genetically modified ingredients, artificial unhealthy fats, as well as foods containing excessive amounts of salt or sugar. 
Orthorexics consider these foods to be impure because they contain artificial substances or large quantities of what they deem to be empty calories.
Orthorexics plan their life around food as their diet becomes the most important part of their lives. they may even go so far as to pack their own food to eat at a restaurant, social, or family gatherings.  Many orthorexics exhibit an intense fear of eating in front of people so instead prefer to isolate themselves so that they can control their diet as much as possible without receiving negative comments from others.
In addition, many orthorexics feel guilty and sorrowful if they eat a food item not considered pure.  As damage control they may cut out additional foods, restrict their caloric intake on subsequent days, fast, or increase their physical activity.
In addition to having a self-created list of approved and unapproved foods, many orthorexics insist on consuming meals at extremely specific times.  For example, they may become irritated if they are unable to consume their lunch exactly at 12:00pm due to a conflicting event such as a meeting at work.
Orthorexics may also prepare the same exact foods for certain meals for months on end. For example, they may have exactly one cup of oatmeal with fruit in the morning, a salad for lunch, and chicken with rice and broccoli in the evening every single day. While this might sound moderately healthy to the average person it can lead to nutritional deficiencies due to lack of diet variation.
The Bratman Orthorexia Test (BOT), designed by Steven Bratman back in the mid-1990s, asks the following ten questions to determine an individual's obsession with eating healthy food. Dr. Bratman believes that those answering yes to four or five questions indicates that one should relax more when it comes to food and those answering yes to all questions have orthorexia: 
Do you spend more than 3 hours a day thinking about your diet? Do you plan your meals several days ahead? Is the nutritional value of your meal more important than the pleasure of eating it? Has the quality of your life decreased as the quality of your diet has increased? Have you become stricter with yourself lately? Does your self-esteem get a boost from eating healthily? Have you given up foods you used to enjoy in order to eat the right' foods? Does your diet make it difficult for you to eat out, distancing you from family and friends? Do you feel guilty when you stray from your diet? Do you feel at peace with yourself and in total control when you eat healthily?Two other tests commonly used to diagnosis orthorexia include ORTO-15 and ORTO-11. Both tests have 11 of the same questions but ORTO-11 removed four items not deemed statistically significant.  A score of less than 40 on the ORTO-15 may indicate strong orthorexic tendencies. 
You may see and be tempted to complete these tests online but it's vital you only take the results at face value. Consulting with a psychologist or health care professional is another critical component for diagnosing orthorexia.
Orthorexia Nervosa ImpactsOrthorexics may believe they're eating to optimize health but the reverse effects tend to occur. By cutting out a significant number of foods deemed unhealthy they significantly decrease their meal diversity and caloric intake.  Failure to consume enough calories from a variety of food sources can lead to muscle loss, an impaired immune system, as well as serious vitamin and mineral deficiencies.
Orthorexia may also decrease a person's ability to eat intuitively.  The individual may be so used to consuming specific foods as specific times of the day they may purposefully prevent themselves from eating when they're hungry and overeat if they are not hungry. Eating intuitively is a powerful tool for maintaining sanity during the fitness and body transformation journey.
Unfortunately, the research on orthorexia is relatively sparse since it's not an eating disorder officially recognized by the medical community. A meta-analysis using the Düsseldorf Orthorexia Scale found that orthorexia affects between 1 and 2% of the general population worldwide. 
Based on a global population of 7.4 billion this equates to between 74 and 148 million people. On the higher end, one study of 404 subjects supposedly representing the general population found that about 7%, or 28 individuals, exhibited orthorexia. 
Two studies identified yoga practitioners and healthcare professionals as very high risk populations for developing orthorexia. Up to 86% of yoga practitioners and between 35 and 58% of healthcare professionals may suffer from orthorexia. 
We should hardly be surprised to see that professions placing an exceptionally high emphasis on health also significantly increase the likelihood of developing orthorexia.
I would like to reiterate that an emphasis on eating healthy does not automatically classify you as an orthorexic. Orthorexic individual spend an inordinate amount of time, planning, and energy on healthy food, punish themselves when they eat an unapproved food, and use food to create an identity to isolate yourself and avoid bigger issues in life. 
If you fear that you or someone you know exhibits strong symptoms associated with orthorexia then please seek help as soon as feasible.