1. Introduction
Obesity is considered as one of the significant problems in developing countries and a threat to public health worldwide, causing various diseases [1]. People with eating disorders have problems in emotion regulation and lack the skills needed to deal effectively with emotion management [4]. Difficulties in emotion regulation include the use of maladaptive strategies for responding to emotions, being risk factors for the occurrence and persistence of various psychiatric as well as eating disorders such that binge eating acts as a response to unpleasant emotions in obese people who seek treatment [6].
Another psychological variable affecting emotion regulation in obese people is metacognitive beliefs. Dysfunctional metacognitive beliefs can be related to having a negative body image and experiencing negative emotions in obese people [8].
There are several reasons that the metacognitive model can be useful for understanding eating disorders; for example, eating disorders appear to have many similarities to other types of worry-related mental disorders such as Generalized Anxiety Disorder (GAD) and Obsessive-Compulsive Disorder (OCD) in which metacognitive beliefs play a significant role. Also, rumination, a target of metacognitive therapy, is significantly associated with eating disorders [9].
Dysfunctional metacognitive beliefs, reduced self-esteem, and feelings of inadequacy undermine the abilities of obese people, making them reliant on others. Studies have shown that compared with normal-weight people, obese people are more involved in communicating with others and feel the need to do so; even in this way they control others [10]. In fact, they think that having relationships with others means that they are accepted by them, and this causes problems for obese people in social communications and interpersonal relationships. In this regard, we investigate the predictive role of metacognitive beliefs, difficulty in emotion regulation, and codependency in obese women compared to healthy-weight subjects.

2. Materials and Methods
This research was a causal-comparative study performed on 80 subjects, including 40 obese people referring to a specialized weight loss clinic in Tehran and 40 subjects with average weight. They were selected through convenience sampling method, and they completed research tools. 
The tools used in the research were Wells & Cartwright-Hatton’s Metacognitions Questionnaire, a 30-item self-report scale that measures the subjects’ metacognitive beliefs [14]; Difficulties in Emotion Regulation Scale, a 36-item self-report tool designed by Gratz and Roemer, with acceptable internal consistency in Iran [17]; the Codependency Assessment Questionnaire developed by Hughes-Hummer, Martsalef, and Zeller designed to measure the characteristics of codependency in the subjects with 25 questions, also with a good internal consistency in Iran [19].
3. Results
In this study, discriminant function analysis was used to analyze the data. Results of the discriminant function with three variables of metacognitive beliefs, the difficulty in regulating emotion, and codependency can correctly classify 95% of obese and 97.5% of healthy average weight subjects. In other words, the overall function was able to classify 96.25% of all subjects correctly.
4. Discussion
The purpose of the present study was to identify obese people from normal-weight people based on metacognitive beliefs, difficulty in emotion regulation, and codependency.The results showed that metacognitive beliefs could significantly discriminate between obese individuals and normal-weight ones. Compared to those who do not, people with obesity who seek treatment for weight loss experience more psychological distress such as depression, anxiety, etc [22]. Research findings suggest that even mild depression is associated with a significant increase in negative metacognitive beliefs [20]. Thus, depression and anxiety in obese people can increase dysfunctional metacognitive beliefs, which themselves may cause depression and anxiety in obese people. Metacognitive therapy by way of eliminating worry and rumination, and developing a flexible metacognitive style can be useful for these people.
One of the psychological problems of obese people is the management of their emotions [25]. Studies show that emotional eating is associated with negative feelings such as anger, depression, discomfort, anxiety, and loneliness and often occur in stressful moments of life. Therefore, it is not unlikely that people with obesity use eating as a coping strategy when it comes to difficulty in regulating emotion and that weight gain occurs rapidly once emotional regulation fails.
Codependency is another psychological variable that has a significant relationship with different levels of body mass index. There is a clear relationship between obesity and major interpersonal problems [26]. Inability to solve interpersonal problems, fear of negative judgments by others, unfavorable social comparison, fear of closeness and establishing intimacy, and suspicion in interpersonal relationships are the causes of interpersonal problems in people with obesity [29, 30].
By being highly codependent, obese people believe they are able to control others’ mentality and be accepted by them, and by developing codependency with others, they believe they can control the fear of rejection and others’ negative evaluation. Also, emotional eating occurs mostly when people are alone at home. This may reflect the role of others in controlling their emotional eating. However, the problems resulting from communication with others and codependency can itself trigger emotional eating.
The findings of the present study confirm the theories and explanations about the significant role of psychological factors in obesity and overweight. In distinguishing the two groups of obese and normal-weight people, the variables of metacognitive beliefs, difficulty in emotion regulation, and codependency have significant roles. Therefore, it is suggested that these variables be considered in the prevention and treatment of obesity.
Ethical Considerations
Compliance with ethical guidelines
This research was approved by Kharazmi University (Ethical Code: IR.KHU.REC.1397.41).
Funding
This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.
Authors' contributions
All authors met standard criteria of writing based on the recommendations of the International Committee of Medical Journal Publishers (ICMJE).
Conflicts of interest
The authors declare no conflict of interest .


References