Researchers at York University's Faculty of Health 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.

In the first exhaustive review of the psychosocial risk factors associated with orthorexia nervosa, York University psychology researchers examined all studies published up until the end of 2018 in two popular databases. They looked at studies that examined how orthorexia nervosa is related to psychosocial risk factors that predisposed or made an individual vulnerable to or more likely to develop the condition. They then amalgamated all available findings for each risk factor to reach conclusions about which psychosocial factors were most reliably associated with the condition.

"The long-term impact of these findings is that they will lead to better recognition among healthcare providers as well as members of the public that so-called healthy eating can, in fact, be unhealthy. It can lead to malnourishment or make it very difficult to socialize with people in settings that involve eating. It can also be expensive and time-consuming," says Jennifer Mills, associate professor in the Department of Psychology and senior author on the study.

"When taken to the extreme, an obsession with clean eating can be a sign that the person is struggling to manage their mental health."

Previous research has shown that unlike individuals with anorexia nervosa who restrict calories to maintain very low body weight, people who have the condition have a fixation with the quality of food eaten and its preparation rather than the number of calories. Over time, they spend increasing amounts of time and effort purchasing, planning, and preparing pure and healthy meals, which eventually becomes an all-consuming obsession that interferes with other areas of life and results in weight loss.

One of the main reasons for conducting this study was that current research on the condition is limited. Unlike other eating disorders, such as anorexia, bulimia, orthorexia is not recognized in standard psychiatric manuals for healthcare providers.

"It was surprising to me that the overwhelming majority of the articles in this field were of neutral-poor quality, indicating that the results of these studies must be interpreted with caution," says Sarah McComb, a Master's student in Mills' lab and first author of the study. "It really suggests a call for more valid measurement tools of orthorexia, so that more reliable conclusions can be drawn about the true prevalence of orthorexia in the population and which psychosocial factors really put a person at risk for developing orthorexia nervosa."

Researchers found the literature consistently showed that those who have obsessive-compulsive traits, depression and a previous eating disorder, and/or are preoccupied with their appearance and body image, are more likely to be at risk for developing the condition. Other eating habits such as being a vegetarian or vegan also put individuals at higher risk for developing orthorexia nervosa. Lacto-vegetarians were at highest risk for the condition and people who are on a strict eating schedule, spending large amounts of time preparing meals, were also at greater risk.

"In our research, we found equal rates of men and women who struggle with symptoms of orthorexia nervosa," said Mills. "We still think of eating disorders as being a problem that affects mostly young women. Because of that assumption, the symptoms and negative consequences of orthorexia nervosa can fly under the radar and not be noticed or taken seriously."

Researchers say developing a consistent definition of orthorexia nervosa will make it easier for health researchers to develop reliable measures and provide better diagnosis and treatment of the condition.