In this study, LISREL was used to test the construct validity of the C-BES. The results from CFA revealed that the overall model fit was good, and there was a good and acceptable relationship between the factor structures. Although the χ2 value showed a significant difference (p < 0.01), it is important to note that the chi-square test is sensitive to sample size, and most differences will appear statistically significant when the sample size is large [31,32,33]. A further examination at χ2/df showed that the adjusted value was 2.66, which was smaller than the standard value of 3 [34]. In this study, most of the indices met the criteria of good model fit. The testing results were in line with the original version of the scale and consistent with findings by researchers from other countries [15, 17]. When compared with other studies, our study provided two-factor results instead of one-factor results [5, 16], and different results could also come from recruiting participants of different age groups. We recommend testing participants of various ages and BMI in future studies to develop a BE screening tool that applies to the general population.

In terms of content validity testing, the original author of the scale, Dr. Gormally, was invited to assist in reviewing the content of the backward translation. Seven Taiwanese experts were also invited to help with the review of the questionnaire translation, including two psychiatrists with expertise in binge eating disorders, three mental health experts specializing in eating disorder patient care, and two linguistics professors. After two consensus meetings and revisions, the content validity indices (item-level content validity index; I-CVI) for all questions (16 items, a total of 62 options) were 1. Only three options had indices of 0.86, which were well above the standard value of 0.78 for I-CVI [35]. This result showed that the translated scale was very representative, and the expert content validity was excellent. This research advocates the need to have five to seven expert reviewers in any future translation of study instruments. Furthermore, the expertise of the reviewers should be aligned with the area of the review to achieve effectiveness in cross-cultural language communication [20, 36].

In testing criterion-related validity, clinical evidence showed that BED was closely related to bulimia nervosa (BN), and both have obvious binge eating symptoms. Patients with BN also regularly exhibit compensatory behaviors, such as rigorous exercise, induced vomiting, laxative use, or fasting [1, 37, 38]. This study used BITE, the scale for diagnosing bulimia, as the key indicator for assessing criterion-related validity. The testing results were consistent with the empirical data, indicating a positive and significant relationship. The results support the C-BES as a validity tool for assessing BE behaviors among overweight or obese college students in Taiwan.

In terms of reliability, the internal consistency of the C-BES was good (α = 0.83), well above the acceptable value of 0.7, indicating good reliability [39]. Although the corrected item-total correlations (rtot) for items 6 and 13 were 0.26, the two items were retained in the model, as they were essential in identifying important characteristics of BED, including the extent of eaters' guilt after overeating and dietary abstinence between meals. The other reason was that the removal of individual questions did not increase the internal consistency of the overall scale. It is recommended that item clarity be further enhanced in terms of semantics to increase the level of discernment in the future. The results of the test–retest reliability were quite good. The scores of the two repeated measurements, with a one-month interval, had a significant correlation, and the ICC exceeded the reference value of 0.8 [18]. The C-BES had good reliability and stability and can be employed in large-scale surveys cost-effectively.

Demographic data suggested that subjects’ BES scores were significantly associated with their gender and BMI, which is consistent with the findings of most Western studies [40,41,42]. In addition, a recent national survey on young adults in the United States (n = 14,322; aged between 18 and 24 years) found that the prevalence of binge eating among overweight or obese individuals was substantially higher than that among normal or underweight individuals. More specifically, the prevalence was 29.3% versus 15.8% among women and 15.4% versus 7.5% among men. Subsequent logistic regression analysis indicated that the risk (odds ratio) of women developing binge eating was 2.32 times that of men (95% CI = 2.05–2.61) [43]. This result revealed the need for school health units to focus on the binge eating problem among college students and prioritize overweight or obese women for screening.

Since this study focused on college students, the inclusion criteria limited the age of participants to 18–24 years old. Such a narrow range in age may cause an insignificant difference in statistical testing. The results of this study support the above viewpoints and recommend that future studies be conducted to thoroughly explore the psychological factors associated with binge eating among people of diverse cultures and different genders to help develop positive coping strategies for regulating emotional stress.

This study adopted convenience sampling to survey young students from five colleges and universities characterized by their focus on developing healthcare programs. As most of these schools are in the metropolitan area of northern Taiwan, this study may not reach all young people with binge eating disorders. It is suggested that future studies should include diversified participants, schools of higher heterogeneity, or even those of different age groups to enhance the applicability and popularity of the scale. In addition, this study defined overweight and obese individuals based on World Health Organization [WHO] recommendations. The diagnostic criteria for overweight (BMI ≥ 24 kg/m2) and obese (BMI ≥ BMI 27 kg/m2) were based on data published by Taiwan’s Ministry of Health and Welfare [22]. The cutoff BMI values were different from the standards of Western countries. Due to racial differences and other discrepancies in disease-related conditions, how to clearly define the criteria for overweight and obesity is a highly discussed topic. It is recommended that future studies adopt multiple indicators, such as the body fat ratio, waist circumference, or waist-hip ratio (WHR), to diagnose overweight and obesity holistically.