2.2. Study Procedure and Research Tool

The research tool was an anonymous questionnaire consisting of five parts: a personal questionnaire, the author’s questionnaire on diet and eating habits, the SCOFF questionnaire by Morgan et al. [25], the TFEQ-13 questionnaire in the Polish adaptation by Anna Dzielska et al. [26] and the ORTO-15 questionnaire by Donini et al. [27].

Demographic information such as age, gender, and education was collected. Anthropometric measurements reported by the subjects included height and current body weight. From these data, BMI was calculated and interpreted according to World Health Organisation recommendations. The breakdown by body mass index was as follows: underweight <18 kg/m²; normal 18–24.99 kg/m²; overweight 25–30 kg/m²; obese >30 kg/m² [28]. Health status questions asked about the presence of diet-related diseases that may affect eating behavior.

The SCOFF questionnaire was used to assess the prevalence of the possible presence of eating disorders. It consists of five questions addressing the basic characteristics of disorders such as anorexia nervosa and bulimia nervosa. Possible answers are ‘yes’ or ‘no’. Giving two or more affirmative answers indicates the presence of an eating disorder. It is a simple screening tool that is not used for diagnosis but to suggest the likelihood of an eating disorder in a given case [25].

The Polish adaptation of the Three-Factor Eating Questionnaire (TFEQ-13) was used to assess cognitive-behavioral aspects related to eating. In the original version by Stunkard and Messik, the TFEQ scale contained 51 questions. It was shortened to 18 questions by Karlsson and then translated and reduced on the basis of testing. In the final version used for the study, the TFEQ-13 scale contains 13 questions, which are divided into three subscales: restrictive eating (control over food intake to control body weight; R1–R5), uncontrolled eating (general difficulties in regulating eating; J1–J5) and emotional eating (overeating in depressed mood states; E1–E3). Responses to each question were standardized on a 4-point scale and interpreted by scoring from 0 to 3 (definitely no—0 points, rather no—1 point, rather yes—2 points, definitely yes—3 points). Question 13, which involves indicating a number on a scale from 0 to 8, is coded differently: values 1 and 2 are 0 points, 3 and 4 are 1 point, 5 and 6 are 2 points, and 7 and 8 are 3 points. Values were calculated separately for each component, and the higher the score on a subscale, the greater the severity of impairment in that area [26,29,30].

Another questionnaire used for the study was the ORTO-15, which is the most commonly used measure in screening for symptoms of orthorexia. The questionnaire consists of 15 questions, and responses were created on a 4-point Likert-type scale, including statements of ‘always’, ‘often’, ‘rarely’, or ‘never’. The scoring of questions numbered 3, 4, 6, 7, 10, 11, 12, 14, and 15 is as follows: ‘always’ is 1 point, ‘often’ is 2 points, ‘rarely’ is 3 points, and ‘never’ is 4 points. For questions numbered 2, 5, 8, and 9: ‘always’ is 4 points, ‘often’ is 3 points, ‘rarely’ is 2 points, and ‘never’ is 1 point. For questions numbered 1 and 13: ‘always’ is 2 points, ‘often’ is 4 points, ‘rarely’ is 3 points, and ‘never’ is 1 point.

As suggested by the authors of the questionnaire, a score below 40 points indicates the presence of orthorexia symptoms [27], while the Polish validation of the questionnaire proposed a cut-off point of 35 points, suggested by the nature of the distribution of the orthorexia risk index in the study population [31]. The study used the interpretation that a score below 35 points indicates the presence of orthorexia symptoms.