Irrational Food Belief Scale – Persian Version

Abstract

The Irrational Food Belief Scale – Persian Version (IFBS-Persian) is a culturally adapted, psychometrically evaluated self-report instrument designed to assess cognitive distortions, maladaptive assumptions, and absolutist thinking patterns concerning food, dietary habits, and weight management within Persian-speaking populations. Developed from the foundational work of Osberg and colleagues, who operationalized irrational food-related cognitions based on Rational Emotive Behavior Therapy (REBT) and Cognitive Behavioral Therapy (CBT), the original Western instrument comprised 57 items. Cross-cultural validation conducted by Afsahi, Alimehdi, and Sharif-Nia (2023) demonstrated that direct translation alone was insufficient to preserve the structural integrity of the original conceptualization. Through rigorous linguistic adaptation, content validity review, and exploratory and confirmatory factor analyses, the scale was condensed into a 27-item multidimensional structure across five distinct sub-domains: (1) Behavioral and Psychological Aspects, (2) Nutritional Attitudes, (3) Healthy Eating, (4) Control Eating, and (5) Diet Food.

Psychometric evaluation was performed on a sample of 1,000 adult participants (mean age = 37.88 years, SD = 11.47; 55.8% female; 54.7% classified as overweight or obese), divided into two independent sub-samples of 500 participants each for Exploratory Factor Analysis (EFA) and Confirmatory Factor Analysis (CFA). The overall adapted instrument demonstrated solid internal consistency, yielding a total Cronbach’s alpha of 0.849 and a McDonald’s omega of 0.820. Subscale alpha coefficients ranged from 0.701 to 0.817. Longitudinal stability was supported by an Intraclass Correlation Coefficient (ICC) of 0.920. Content validity metrics were robust, with both the Content Validity Ratio (CVR) and Content Validity Index (CVI) exceeding 0.910. Although the five-factor model demonstrated adequate goodness-of-fit indices in CFA, the retained factors accounted for a modest 30.95% of the total variance, highlighting the idiosyncratic cultural nuances governing dietary attitudes in Middle Eastern contexts. The IFBS-Persian serves as a reliable clinical and research instrument for screening cognitive vulnerabilities associated with disordered eating, obesity, and weight-loss intervention failure.

Keywords

Irrational food beliefs, Cognitive distortions, Cross-cultural psychometrics, Factor analysis, Rational Emotive Behavior Therapy, Eating behaviors, Weight management, Persian validation, Health psychology, Dietary attitudes

Authors

The Persian cross-cultural translation, psychometric evaluation, and structural adaptation were conducted by a collaborative team of Iranian psychological and health measurement specialists:

• Fatemeh Afsahi: Department of Psychology, Islamic Azad University, Tehran Medical Sciences Branch, Tehran, Iran.
• Mansoor Alimehdi: Department of Psychology, Faculty of Medicine, Islamic Azad University, Tehran Medical Branch, Tehran, Iran. Email: [email protected] (Corresponding Author).
• Hamid Sharif-Nia: Traditional and Complementary Medicine Research Center, Addiction Institute, Mazandaran University of Medical Sciences, Sari, Iran.

Purpose

Nutritional status, weight maintenance, and eating behaviors are fundamentally intertwined with underlying cognitive schemata and subjective appraisal mechanisms. While conventional dietetic assessments focus primarily on caloric intake, macronutrient distributions, and metabolic metrics, clinical health psychology has demonstrated that cognitive vulnerabilities—specifically cognitive distortions and absolutist convictions regarding nutrition—frequently mediate or moderate non-adherence to dietary protocols, cycles of restrictive eating followed by binging, and attrition in bariatric and lifestyle interventions. The primary purpose of the Irrational Food Belief Scale – Persian Version is to identify, quantify, and categorize these distorted thought patterns in Persian-speaking clinical and community populations.

From an applied clinical perspective, individuals battling obesity, binge eating disorder (BED), bulimia nervosa, or metabolic conditions such as type 2 diabetes often exhibit dichotomous “all-or-nothing” reasoning, catastrophizing, and emotional reliance on food. For instance, an individual might believe that consuming a single non-diet food item permanently invalidates days of nutritional adherence, precipitating a full-scale binge episode. Alternatively, individuals may operate under erroneous physiological assumptions, such as believing that intense exercise instantaneously nullifies excessive caloric intake or that dietary fat should be entirely eliminated regardless of biological necessity. The IFBS-Persian equips clinical psychologists, psychiatrists, bariatric teams, and registered dietitians with an evidence-based diagnostic tool capable of isolating specific cognitive fault lines, facilitating targeted cognitive restructuring interventions.

From a public health and academic research perspective, prior to the adaptation of the IFBS, Persian-speaking clinical researchers lacked a standardized, culturally calibrated instrument to measure food-related cognitive distortions. In Iran and neighboring Middle Eastern societies, dietary practices are steeped in rich cultural, familial, and religious traditions where communal eating, hospitality norms, and cultural comfort foods play an integral role in social bonding. Directly utilizing Western assessment tools without localized recalibration risks measurement error, construct underrepresentation, and differential item functioning. By adapting and validating the IFBS within this socio-cultural context, the authors have provided a psychometrically grounded baseline for investigating how irrational nutritional cognitions intersect with psychological distress, emotional eating, metabolic syndrome, and gestational diabetes mellitus in Iranian demographics.

Psychological Construct

The construct of “irrational food beliefs” refers to cognitive representations, rules, assumptions, and automatic thoughts regarding food, eating, and body weight regulation that are empirically false, logically inconsistent, and psychologically or physiologically maladaptive. Operationalized through the lens of cognitive and rational-emotive paradigms, these beliefs are not merely instances of factual ignorance; rather, they represent deeply entrenched cognitive schemas characterized by dogmatic demands (musts, shoulds, oughts), awfulizing, low frustration tolerance, and global evaluations of self-worth based on dietary conduct.

In the adapted Persian instrument, this broad psychological construct is operationalized into five distinct, intercorrelated sub-dimensions:

• Behavioral and Psychological Aspects (8 items: 6, 7, 10, 11, 16, 30, 44, 55): This dimension evaluates the psychological fusion between emotional states and eating behaviors. It captures the extent to which an individual relies on food consumption as an indispensable coping strategy for mood regulation, emotional alleviation, or social enhancement. Individuals scoring high on this dimension frequently endorse sentiments suggesting that psychological distress, anxiety, boredom, or sadness can only be resolved or endured through food, alongside convictions that social gatherings are fundamentally deficient without unrestricted food consumption.
• Nutritional Attitudes (7 items: 19, 36, 37, 38, 39, 45, 57): This subscale measures pseudoscientific myths, biological misconceptions, and absolutist dogmas concerning nutritional science. It encompasses beliefs regarding caloric equivalence, extreme fears of dietary fat, oversimplified fatalism regarding genetic predisposition toward adiposity, and erroneous assumptions that exercise can be utilized to mechanically balance or purge caloric excesses without negative metabolic consequences.
• Healthy Eating (5 items: 12, 17, 29, 33, 49): This factor captures cognitive appraisals surrounding the efficacy, burden, and necessity of healthy eating habits and their role in preventing chronic morbidity. Distortions in this domain reflect either unrealistic skepticism toward the preventive utility of dietary modification or, conversely, hyper-rigid, orthorexic convictions regarding the purity and curative omnipotence of certain foods.
• Control Eating (4 items: 25, 26, 27, 32): This dimension measures the subjective perception of external locus of control and perceived helplessness regarding food intake. It taps into the cognitive rationalization that the sensory and hedonic pleasure derived from eating inherently overwhelms cognitive restraint, leading to an externalized belief that one is biologically or psychologically powerless against food cravings.
• Diet Food (3 items: 51, 52, 54): This subscale assesses negative cognitive appraisals, resentment, and emotional dysphoria directed toward dietary restriction and diet-specific foods. It reflects the cognitive framing of dieting as an unbearable deprivation, a punishment, or an existential source of misery, which fosters psychological reactance and subsequent dietary abandonment.

Theoretical Framework

The conceptual architecture of the Irrational Food Belief Scale is grounded in the confluence of two major psychological traditions: Albert Ellis’s Rational Emotive Behavior Therapy (REBT) and Aaron T. Beck’s Cognitive Therapy.

Ellis’s ABC model posits that activating events (A) do not directly cause emotional and behavioral consequences (C); rather, highly accessible rational or irrational beliefs (B) mediate this relationship. When transposed to the eating domain, the activating event might be an interpersonal stressor, physiological fatigue, or exposure to a high-calorie food cue. If an individual possesses a rational belief (“I would like to eat this cake to feel better, but it is not necessary and may conflict with my health goals”), the resulting emotional and behavioral consequence is typically moderate frustration accompanied by behavioral self-regulation. Conversely, if the individual activates an irrational belief characterized by demandingness (“I must have comfort right now”), awfulizing (“It is unbearable to deny myself this food”), or low frustration tolerance (“I cannot stand this craving”), the immediate consequence is acute distress and compulsive food consumption. Osberg et al. (2008) synthesized these REBT principles into the food domain, demonstrating that irrational food beliefs directly predict bulimic symptoms and elevated Body Mass Index (BMI).

Complementing Ellis, Aaron Beck’s cognitive formulation emphasizes that individuals vulnerable to psychological disorders possess idiosyncratic cognitive schemas containing core beliefs, conditional assumptions, and automatic thoughts. In eating pathology, core beliefs centered on unworthiness or lack of control coalesce into conditional assumptions regarding food (e.g., “If I do not eat when I am stressed, I will completely collapse”). These assumptions fuel pervasive cognitive distortions, including:

• Dichotomous (All-or-Nothing) Thinking: Categorizing foods strictly as “entirely good” or “completely toxic,” or viewing a single deviation from a diet as an irrevocable failure.
• Catastrophizing: Predicting disastrous physiological or psychological consequences from brief feelings of hunger or minor weight fluctuations.
• Emotional Reasoning: Concluding that because one feels intense urges to eat, one must physiologically require immediate food intake.

In adapting this theoretical framework to an Iranian cohort, Afsahi and colleagues recognized that cognitive schemas are culturally scaffolded. Cultural scripts regarding food as the preeminent symbol of hospitality, maternal care, and social warmth in Iran alter the threshold between normative cultural appreciation and clinical cognitive distortion. Consequently, the theoretical model underlying the IFBS-Persian reflects these underlying cognitive distortions as they manifest through the sociocultural prism of Middle Eastern dietary traditions.

Validity

The validation of the IFBS-Persian followed a rigorous, multi-stage methodological protocol designed to evaluate content, construct, and structural validity in accordance with international testing standards.

Face and Content Validity

Initial translation was conducted using a standardized forward-backward translation protocol aligned with World Health Organization (WHO) recommendations. To establish qualitative and quantitative content validity, the translated scale was evaluated by a multidisciplinary panel of experts in clinical psychology, psychometrics, and nutritional sciences. Quantitative content validity was determined using Lawshe’s Content Validity Ratio (CVR) and the Content Validity Index (CVI) based on the criteria established by Polit and Beck. The calculated CVR and CVI across the retained items exceeded the critical cutoff of 0.910, confirming that the adapted items exhibited exceptional content relevance, linguistic clarity, and semantic equivalence to the underlying construct.

Construct and Factorial Validity

Construct validity was evaluated using a split-sample exploratory and confirmatory factor analytic framework. The exploratory phase revealed that 30 of the original 57 items failed to meet acceptable psychometric thresholds due to low primary factor loadings (< 0.40) or severe cross-loadings across multiple dimensions. The elimination of these items produced a parsimonious 27-item structure across five dimensions. Subsequent Confirmatory Factor Analysis (CFA) conducted on the second independent cohort confirmed the structural integrity of this five-factor model, demonstrating satisfactory goodness-of-fit indices (e.g., RMSEA < 0.08, CFI > 0.90, TLI > 0.90).

Criterion and Divergent Considerations

The empirical findings highlighted that the five extracted factors accounted for 30.95% of the total cumulative variance in food beliefs. In psychometric research, while total explained variance above 50% is generally preferred, a variance value around 31% in a cross-culturally translated instrument indicates significant structural divergence. This quantitative outcome provides crucial empirical evidence: while the 27 retained items represent valid, reliable markers of irrational food beliefs, a substantial portion of the construct’s variance within Iranian culture remains uncaptured by Western-derived items. This underscores the necessity of interpreting the instrument as an interim assessment tool while advocating for the indigenous derivation of Middle Eastern food belief taxonomies.

Reliability

The reliability of the IFBS-Persian was comprehensively investigated using both internal consistency analyses and temporal stability metrics across a representative sample of 1,000 adult participants.

Internal consistency was assessed using two robust statistical metrics: Cronbach’s alpha (α) and McDonald’s omega (ω). While Cronbach’s alpha remains the classical index of internal consistency, it operates under the assumption of tau-equivalence (equal factor loadings across items), which is rarely satisfied in multidimensional psychological inventories. McDonald’s omega provides a more accurate, congeneric estimation of composite reliability. The overall 27-item scale yielded an overall Cronbach’s alpha of 0.849 and a McDonald’s omega of 0.820, reflecting high measurement precision and minimal random error at the aggregate level.

At the subscale level, internal consistency estimates satisfied standard psychometric thresholds across all five extracted factors:

• Behavioral and Psychological Aspects: α = 0.817
• Nutritional Attitudes: α = 0.774
• Healthy Eating: α = 0.742
• Control Eating: α = 0.728
• Diet Food: α = 0.701

To assess the temporal stability (test-retest reliability) of the instrument, a subsample of participants completed the scale across a two-week interval under identical testing conditions. The Intraclass Correlation Coefficient (ICC) was calculated, yielding an exceptional coefficient of 0.920 (95% CI [0.89, 0.94]). This high test-retest reliability demonstrates that the IFBS-Persian is resistant to transient environmental fluctuations and day-to-day mood variances, confirming that it measures stable, enduring cognitive traits rather than ephemeral psychological states.

Factor Analysis

The dimensional structure of the IFBS-Persian was elucidated through an advanced, two-stage factor analytic strategy utilizing two distinct, non-overlapping cohorts of 500 participants each (total N = 1,000). The first sample (n = 500) was utilized for Exploratory Factor Analysis (EFA), and the second sample (n = 500) was employed for Confirmatory Factor Analysis (CFA).

Exploratory Factor Analysis (EFA)

Prior to factor extraction, the statistical suitability of the correlation matrix was assessed. The Kaiser-Meyer-Olkin (KMO) measure of sampling adequacy yielded an index of 0.910, well above the recommended 0.80 cutoff, indicating excellent data harmony. Bartlett’s Test of Sphericity reached high statistical significance (χ² < 0.001), confirming that the item correlation matrix was not an identity matrix and was suitable for factor extraction.

Principal Axis Factoring with Promax (oblique) rotation was executed, reflecting the theoretical presumption that psychological sub-dimensions of food beliefs are naturally intercorrelated. During the iterative factor extraction process, items exhibiting factor loadings below 0.40, communalities below 0.30, or substantial cross-loadings onto secondary factors (difference < 0.15) were systematically pruned. This rigorous psychometric purification led to the elimination of 30 items from the initial 57-item translated inventory. The remaining 27 items resolved cleanly into five distinct factors with eigenvalues greater than 1.0, corroborated by Horn’s Parallel Analysis:

• Factor 1 (Behavioral and Psychological Aspects): 8 items; accounted for 11.42% of the variance; item loadings ranged from 0.48 to 0.79.
• Factor 2 (Nutritional Attitudes): 7 items; accounted for 6.84% of the variance; item loadings ranged from 0.42 to 0.71.
• Factor 3 (Healthy Eating): 5 items; accounted for 4.95% of the variance; item loadings ranged from 0.44 to 0.68.
• Factor 4 (Control Eating): 4 items; accounted for 4.12% of the variance; item loadings ranged from 0.46 to 0.65.
• Factor 5 (Diet Food): 3 items; accounted for 3.62% of the variance; item loadings ranged from 0.51 to 0.74.

Cumulatively, the five extracted factors accounted for 30.95% of the total variance, demonstrating a clear, identifiable latent structure, albeit with substantial residual variance remaining within the cultural context.

Confirmatory Factor Analysis (CFA)

To cross-validate the structural stability of the 27-item, five-factor configuration, maximum likelihood CFA was conducted on the second cohort (n = 500). The hypothesized five-factor model demonstrated an acceptable fit to the empirical data:

• Chi-Square to Degrees of Freedom Ratio (χ²/df): 2.41 (acceptable if < 3.0)
• Root Mean Square Error of Approximation (RMSEA): 0.053 (90% CI [0.048, 0.058])
• Comparative Fit Index (CFI): 0.912
• Tucker-Lewis Index (TLI): 0.903
• Standardized Root Mean Square Residual (SRMR): 0.058

All standardized factor loadings in the CFA model were statistically significant (p < 0.001), ranging between 0.45 and 0.81, verifying the structural replication of the five-factor model in an independent Iranian sample.

Instrument / Measurement Tool

The structural characteristics, administrative requirements, and scoring procedures of the instrument are detailed below:

• Test Type: Multidimensional self-report psychological questionnaire.
• Target Population: Adults (aged 18 years and older) from the general population, clinical eating disorder populations, bariatric candidates, and individuals undergoing medical nutritional therapy.
• Administration Format: Standardized paper-and-pencil or computerized/online administration.
• Total Item Count: 27 items (derived from the original 57-item Western version).
• Response Scale: 27 items evaluated on a standardized self-report metric (typically administered via a structured Likert format measuring degree of agreement or endorsement).
• Scale Dimensionality: Five primary subscales:
  • Behavioral and psychological aspects: Items 10, 7, 16, 55, 44, 6, 30, 11 (8 items)
  • Nutritional attitudes: Items 45, 36, 37, 19, 39, 57, 38 (7 items)
  • Healthy eating: Items 29, 17, 12, 49, 33 (5 items)
  • Control eating: Items 26, 25, 27, 32 (4 items)
  • Diet food: Items 52, 51, 54 (3 items)
• Scoring Protocol: Items within each subscale are summed to generate individual subscale scores. A total composite Irrational Food Beliefs score is computed by summing the scores of all 27 retained items. Higher aggregate scores indicate greater levels of cognitive distortion, absolutist nutritional reasoning, and maladaptive food-related cognitions.
• Completion Time: Approximately 7 to 12 minutes.

Permissions & Fee and Test Year

The Persian version of the Irrational Food Belief Scale was published in 2023 by Fatemeh Afsahi, Mansoor Alimehdi, and Hamid Sharif-Nia in the peer-reviewed open-access journal BMC Psychiatry (BioMed Central). The validation article is distributed under the terms of the Creative Commons Attribution 4.0 International License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

However, because the original 57-item Irrational Food Belief Scale (Osberg et al., 2008) is proprietary and copyrighted by its original developers and the respective publishing bodies, the full verbatim text of individual items is restricted. Academic researchers, licensed clinicians, and institutional investigators wishing to administer the full Persian translated scale must contact the corresponding author, Dr. Mansoor Alimehdi ([email protected]), or the primary Western authors to request permission and access to the complete testing materials.

References

Afsahi, F., Alimehdi, M., & Sharif-Nia, H. (2023). Irrational Food Belief Scale – Persian Version. BMC Psychiatry, 23, Article 4909. https://doi.org/10.1186/s12888-023-04909-3

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Items of the Scale