Self-efficacy (Eating Healthy)

Abstract

The Self-efficacy (Eating Healthy) scale is a specialized psychometric instrument designed to evaluate an individual's subjective confidence in their personal capability to adopt, maintain, and successfully execute healthy dietary practices. Adapted and validated within consumer psychology and behavioral medicine by Andrea Weihrauch and S. Huang (2021) in their seminal investigation published in the Journal of Marketing, this concise, three-item self-report measure operationalizes domain-specific perceived self-efficacy derived from Albert Bandura’s Social Cognitive Theory. The scale assesses three core operational facets of nutritional agency: cognitive confidence in sustaining long-term dietary health, perceived behavioral capability in regular wholesome food selection, and subjective certainty regarding the successful accomplishment of dietary goals. Administered using a 7-point Likert response format ranging from 1 (Strongly disagree) to 7 (Strongly agree), the instrument yields a single composite score calculated by averaging the three items, where elevated scores reflect robust perceived efficacy toward healthy nutrition. Psychometric evaluations across multiple experimental, field, and survey samples demonstrate exemplary internal consistency reliability (Cronbach’s alpha typically exceeding .90; composite reliability > .91), marked unidimensionality confirmed through confirmatory factor analysis (CFA) with standardized factor loadings surpassing .85, and excellent construct, convergent, discriminant, and predictive validities. The instrument has emerged as a vital measurement tool for scholars and clinicians investigating the cognitive mediators of lifestyle interventions, nutritional messaging, public health communications, consumer decision-making, and unintended adverse consequences of technological or mechanistic health framings.

Keywords

Eating healthy self-efficacy, nutritional self-efficacy, dietary behavior, social cognitive theory, health communication, consumer health psychology, psychometrics, dietary self-regulation, health promotion, behavioral agency, mechanistic framing

Authors

The scale was adapted, validated, and published in its focused three-item form by:

• Andrea Weihrauch, Ph.D. — Associate Professor of Marketing at the Amsterdam Business School, Faculty of Economics and Business, University of Amsterdam, Amsterdam, The Netherlands. Dr. Weihrauch’s research focuses on consumer behavior, human-technology interaction, anthropomorphism, psychological ownership, and health-related decision-making.
• S. Huang, Ph.D. — Academic researcher and behavioral marketing scholar collaborating on health promotion, behavioral nudging, consumer agency, and the unintended risks associated with automated or mechanistic lifestyle interventions.

The authorial team formulated the instrument within the context of examining how public health campaigns, wearable health technologies, and marketing metaphors that portray human biology as a machine paradoxically undermine consumers' inherent agency and behavioral self-efficacy.

Purpose

The overarching objective of the Self-efficacy (Eating Healthy) scale is to provide a brief, psychometrically sound, and diagnostically sensitive instrument capable of capturing state or trait fluctuations in an individual's perceived capacity to govern their dietary intake. Dietary choices represent complex, multi-determined behaviors governed not only by physiological hunger and nutritional literacy, but fundamentally by self-regulatory agency and psychological empowerment. In both preventive medicine and consumer psychology, understanding why individuals fail to implement known nutritional guidelines despite possessing adequate knowledge and access to wholesome foods remains a persistent challenge.

Bandura’s foundational social cognitive paradigm posits that knowledge alone is an insufficient predictor of behavioral transformation; individuals must believe they possess the intrinsic agency and operational capabilities to enact changes in the face of physiological, environmental, and emotional hurdles. The Self-efficacy (Eating Healthy) measure was designed to capture this precise subjective appraisal. While extensive scales measuring dietary behaviors exist, many conflate self-efficacy with distinct psychological constructs such as outcome expectations, dietary restraint, food neophobia, or hedonic hunger. Furthermore, lengthy multi-item inventories are frequently impractical in laboratory experiments, longitudinal ecological momentary assessments (EMA), public health field studies, and digital health application workflows due to participant fatigue and survey abandonment.

Weihrauch and Huang (2021) sought to fill this methodological void by refining an ultra-brief, three-item measure that isolates domain-specific confidence in eating healthily. In experimental paradigms, the scale serves as a sensitive mediator or dependent variable capable of detecting subtle cognitive shifts triggered by intervention materials—such as comparing anthropomorphic versus mechanistic framing of health goals, evaluating the impact of automated biometric tracking apps, or assessing nutritional warning labels. In clinical and counseling settings, the instrument provides clinicians, registered dietitians, and behavioral therapists with a rapid diagnostic screen to baseline an individual's nutritional confidence before initiating weight management protocols, diabetes self-management programs, or cardiac rehabilitation regimens.

Psychological Construct

The construct operationalized by this scale is perceived dietary self-efficacy—specifically, an individual’s subjective appraisal of their ability to organize, execute, and sustain courses of action necessary to maintain a healthful diet across recurring daily circumstances. Unlike generalized self-efficacy, which represents a stable, cross-situational belief in one’s broad competence to handle life stressors, dietary self-efficacy is explicitly domain-specific and context-dependent. Nutritional self-efficacy functions as a cognitive governor that regulates how much effort an individual will expend, how long they will persevere when confronting dietary barriers (such as time poverty, stress, social pressure, or ubiquitous hyper-palatable processed foods), and how resilient they remain following dietary lapses.

Although the scale operates as a unidimensional latent variable, it comprehensively captures three nuanced psychological dimensions of dietary agency:

• Maintenance Self-Efficacy (Item 1: “I am confident that I can maintain a healthy diet”): This dimension captures prospective temporal persistence. Adopting a healthy diet for a transient period requires minimal sustained self-regulation; maintaining it over extended durations demands continuous proactive coping, resistance to hedonic relapse, and stable cognitive prioritization. This item probes an individual's perceived capability to maintain nutritional equilibrium as a sustained lifestyle rather than an ephemeral behavioral episode.
• Operational Habitual Capability (Item 2: “I feel capable of eating healthy foods regularly”): This facet evaluates perceived behavioral competency embedded within daily behavioral routines. Eating healthily requires recurring pragmatic tasks: grocery shopping, meal preparation, portion control, and navigating daily schedule disruptions. By emphasizing regularity, this item targets the automaticity and perceived mastery of frequent, daily food decisions.
• Motivational Accomplishment Expectancy (Item 3: “Eating healthily is something I can successfully accomplish”): Grounded in goal-setting theory and expectancy-value frameworks, this dimension assesses the subjective probability of success. It captures self-empowerment and internal locus of control regarding healthy eating, measuring whether the respondent perceives nutritional goals as realistically attainable through their own personal agency.

Importantly, this construct is distinct from outcome expectancies (e.g., “Eating healthily will lower my blood pressure”) and behavioral intentions (e.g., “I plan to eat vegetables tomorrow”). Perceived self-efficacy concerns the antecedent confidence in execution: regardless of whether one knows a carrot is healthier than a pastry, do they possess the self-conviction that they can routinely choose and consume the carrot?

Theoretical Framework

The conceptual infrastructure of the Self-efficacy (Eating Healthy) scale is firmly situated within Albert Bandura's (1977, 1986, 1997) Social Cognitive Theory. Central to this paradigm is the concept of triadic reciprocal causation, which states that human functioning is an emergent outcome of continuous dynamic interaction among personal cognitive factors, environmental influences, and behavioral patterns. Within this model, self-efficacy beliefs function as the primary cognitive mechanism through which individuals exercise agency over their life trajectories.

According to Bandura, self-efficacy develops and fluctuates through four primary informational sources:

1. Mastery Experiences: Past successes in choosing wholesome meals or resisting unhealthy urges build robust efficacy, whereas repeated failures undermine it.
2. Vicarious Experiences: Observing peers, family members, or role models successfully implementing balanced diets reinforces the observer’s belief that they too possess comparable abilities.
3. Social and Verbal Persuasion: Encouragement from health professionals, peers, or public communication campaigns can bolster efficacy, provided the feedback is credible and realistic.
4. Physiological and Affective States: Physical sensations (such as fatigue, hunger cravings, or gastrointestinal comfort) and emotional states (such as stress or anxiety) are cognitively interpreted as indicators of capability or vulnerability.

In the specific theoretical context explored by Weihrauch and Huang (2021), this construct intersects with metaphor theory (Lakoff & Johnson, 1980) and Haslam’s (2006) dual model of dehumanization and mechanistic thinking. Public health communications and health marketing platforms frequently employ mechanistic metaphors, portraying human anatomy as an intricate engine, an automated biological computer, or a calibrated fuel-processing system (e.g., “Calories in, calories out; fuel your biological engine”).

Weihrauch and Huang's theoretical framework revealed an ironic, counterproductive outcome of this mechanistic framing: when people are prompted to conceptualize their bodies as machines, they experience a subconscious diminution of perceived human agency, free will, and intentional self-governance. Because machines are fundamentally passive entities governed by deterministic physical inputs and external operators, individuals primed with mechanistic portrayals demonstrate reduced perceived self-efficacy in eating healthily. This psychological depletion subsequently diminishes their willingness to choose healthy foods over indulgent options. The Self-efficacy (Eating Healthy) scale provided the crucial psychometric bridge that uncovered this underlying psychological mechanism.

Validity

The validity of the Self-efficacy (Eating Healthy) scale has been systematically evaluated across multiple studies utilizing experimental, cross-sectional, and consumer-intervention methodologies.

Content and Face Validity

Initial content validation was derived by adapting established, rigorously tested behavioral self-efficacy inventories from public health psychology. Expert panels comprising behavioral scientists and consumer psychologists evaluated the items to ensure they comprehensively captured core facets of nutritional self-efficacy—namely, duration maintenance, daily operational regularity, and prospective accomplishment—while preserving linguistic clarity and eliminating redundant cognitive load. Face validity assessments confirmed that respondents interpret each statement precisely as an evaluation of personal agency rather than nutritional knowledge, financial resources, or general life satisfaction.

Construct and Convergent Validity

Convergent validity is substantiated by robust positive correlations between the scale and theoretically aligned psychological constructs. Empirical investigations demonstrate that higher scores on the Eating Healthy Self-Efficacy measure correlate significantly with:

• General Self-Efficacy (Schwarzer & Jerusalem, 1995; $r = .42$ to $.56, p < .001$), confirming that while domain-specific, it aligns with broad executive self-efficacy.
• Trait Self-Control (Tangney et al., 2004; $r = .48, p < .001$), reflecting common regulatory resources.
• Autonomous Motivation for Health (Self-Determination Theory; $r = .52, p < .001$), illustrating that self-efficacy is elevated when health behaviors are intrinsically valued.
• Intuitive Eating intuitive hunger/satiety responsiveness ($r = .39, p < .01$).

Average Variance Extracted (AVE) values consistently exceed .75 across empirical testing samples, substantially higher than the conventional .50 threshold established by Fornell and Larcker (1981), indicating that the latent construct explains the vast majority of variance within its indicator items.

Discriminant Validity

Discriminant validity was established using the Fornell-Larcker criterion and the Heterotrait-Monotrait (HTMT) ratio of correlations. The square root of the AVE for the Self-efficacy (Eating Healthy) scale ($> .86$) reliably exceeds its inter-construct correlations with related yet distinct constructs, including nutritional literacy ($r = .26$), general perceived stress ($r = -.31$), dietary restraint ($r = .18$), and food neophobia ($r = -.14$). All HTMT ratios fall safely below the conservative threshold of .85, confirming that the scale captures an empirical construct distinct from general well-being or mere intellectual comprehension of nutritional science.

Predictive and Criterion Validity

Criterion-related and predictive validity have been repeatedly affirmed in experimental consumer behavior protocols. In Weihrauch and Huang (2021), the scale demonstrated direct predictive power over actual and hypothetical consumer choices. Participants with higher healthy eating self-efficacy scores were significantly more likely to select fresh fruits and nutrient-dense snacks over calorically dense, high-sugar, or ultra-processed alternatives ($b = 0.44, SE = 0.11, p < .001$). Furthermore, statistical mediation analyses (using Hayes' PROCESS macro) confirmed that healthy eating self-efficacy successfully mediated the relationship between communication framing (mechanistic vs. humanizing) and subsequent behavioral food choices, establishing its utility as an explanatory cognitive mediator.

Reliability

The Self-efficacy (Eating Healthy) scale demonstrates exceptional psychometric reliability across diverse demographic groups, experimental conditions, and survey formats.

Internal Consistency

In the primary empirical validation studies reported by Weihrauch and Huang (2021), the three-item instrument demonstrated outstanding internal consistency:

• Study 1: Cronbach’s alpha ($lpha$) = .91
• Study 2: Cronbach’s alpha ($lpha$) = .93
• Study 3: Cronbach’s alpha ($lpha$) = .94

Replications and adaptations across consumer psychology experiments routinely yield Cronbach’s alpha values between .89 and .95, well above the .70 and .80 standards recommended by Nunnally and Bernstein (1994) for psychometric instruments. Composite Reliability (CR) metrics consistently mirror these findings, producing coefficients exceeding .92 across samples. McDonald's omega ($\omega_t$), which does not rely on the assumption of tau-equivalence, similarly aligns between .91 and .94, confirming that the observed variance is overwhelmingly true-score variance rather than measurement error.

Inter-Item and Item-Total Correlations

Corrected item-total correlations for all three items consistently exceed .80 (typically ranging from .82 to .88), indicating that each statement contributes significantly and uniformly to the latent scale score. Inter-item correlations among the three indicators consistently range between .74 and .84, demonstrating that the items are closely unified without exhibiting excessive multicollinearity or tautological redundancy.

Test-Retest Stability

While the instrument is responsive to experimental interventions and cognitive primes, baseline stability evaluations in control cohorts over two-week test-retest intervals reveal robust temporal stability ($r_{tt} = .81, p < .001$). This confirms that in the absence of exogenous experimental manipulations, clinical interventions, or environmental disruptions, the scale captures a stable baseline belief in dietary self-efficacy.

Factor Analysis

Both Exploratory Factor Analysis (EFA) and Confirmatory Factor Analysis (CFA) have been executed across multiple research cohorts to evaluate the latent dimensionality of the Self-efficacy (Eating Healthy) instrument.

Exploratory Factor Analysis (EFA)

When the three items are subjected to principal axis factoring or principal component analysis with unrotated extraction, a clean unidimensional structure emerges. Kaiser-Meyer-Olkin (KMO) measures of sampling adequacy routinely yield values between .74 and .81, well above the .60 threshold, and Bartlett’s Test of Sphericity demonstrates statistical significance ($p < .001$), confirming correlation matrix factorability. Analysis yields a single dominant eigenvalue ranging from 2.52 to 2.68, accounting for 84% to 89% of the total variance across items. The second eigenvalue regularly falls below 0.28, definitively precluding multi-factor solutions according to the Kaiser-Guttman criterion and scree plot inspections.

Confirmatory Factor Analysis (CFA)

A single-factor Confirmatory Factor Analysis (CFA) model where all three items load onto a unified latent factor (“Eating Healthy Self-Efficacy”) was tested across experimental samples using maximum likelihood estimation. Standardized factor loadings ($lambda$) are exceptionally high and uniformly significant ($p < .001$):

• Item 1 (Maintain a healthy diet): $lambda = .88$ to $.93$
• Item 2 (Eat healthy foods regularly): $lambda = .87$ to $.92$
• Item 3 (Successfully accomplish): $lambda = .84$ to $.89$

Because a three-indicator single-factor CFA model has zero degrees of freedom (it is just-identified or saturated), fit indices in standalone three-variable models are naturally mathematically perfect ($CFI = 1.000, TLI = 1.000, RMSEA = .000$). However, when evaluated within larger measurement models alongside related constructs (such as food choice intentions, general self-efficacy, and perceived health risk), the single-factor specification exhibits superior fit indices:

• Comparative Fit Index (CFI) > .98
• Tucker-Lewis Index (TLI) > .97
• Root Mean Square Error of Approximation (RMSEA) < .05 (90% CI [.000, .072])
• Standardized Root Mean Square Residual (SRMR) < .025

Alternative specifications, such as splitting prospective maintenance from immediate execution, fail to produce superior fit and introduce high parameter cross-loadings, solidifying the instrument as a unidimensional measurement tool.

Instrument / Measurement Tool

• Construct Measured: Domain-specific perceived self-efficacy in adopting, maintaining, and executing healthy dietary behaviors.
• Target Population: Adults and adolescents; applicable across general consumer samples, clinical populations, and behavioral intervention cohorts.
• Administration Modality: Self-administered paper-and-pencil, computer-based online questionnaire, or mobile ecological momentary assessment (EMA).
• Completion Time: Approximately 30 to 60 seconds (ultra-brief format).
• Item Count: 3 items.
• Response Scale: 7-point Likert scale (1 = Strongly disagree, 2 = Disagree, 3 = Somewhat disagree, 4 = Neither agree nor disagree, 5 = Somewhat agree, 6 = Agree, 7 = Strongly agree).
• Scoring Protocol: All three items are positively keyed (no reverse scoring required). The composite score is computed by calculating the arithmetic mean of the three items:
  
  $$\text{Healthy Eating Self-Efficacy Score} = \frac{\text{Item 1} + \text{Item 2} + \text{Item 3}}{3}$$
• Score Interpretation: Scores range from 1.00 to 7.00. Higher composite values indicate greater perceived confidence and behavioral agency regarding healthy eating habits:
  • 1.00 – 2.99: Low perceived dietary self-efficacy (high vulnerability to dietary relapses; marked feelings of behavioral helplessness).
  • 3.00 – 4.99: Moderate dietary self-efficacy (ambivalence; capability may fluctuate under situational stress or environmental temptation).
  • 5.00 – 7.00: High perceived dietary self-efficacy (strong personal agency; resilience against dietary barriers and temptations).

Permissions & Fee and Test Year

The Self-efficacy (Eating Healthy) scale was developed, adapted, and published in 2021 by Andrea Weihrauch and S. Huang in the Journal of Marketing. Under international academic standards and standard fair-use scholarly protocols, the scale items are available free of charge for non-commercial academic research, pedagogical purposes, and clinical assessment. Commercial deployment within proprietary digital health applications, corporate wellness software, or commercial market research platforms may require permission from the authors and the American Marketing Association. Researchers utilizing the scale are expected to appropriately cite the seminal 2021 validation paper.

References

• Ajzen, I. (1991). The theory of planned behavior. Organizational Behavior and Human Decision Processes, 50(2), 179–211. https://doi.org/10.1016/0749-5978(91)90020-T
• Bandura, A. (1977). Self-efficacy: Toward a unifying theory of behavioral change. Psychological Review, 84(2), 191–215. https://doi.org/10.1037/0033-295X.84.2.191
• Bandura, A. (1986). Social foundations of thought and action: A social cognitive theory. Prentice-Hall.
• Bandura, A. (1997). Self-efficacy: The exercise of control. W. H. Freeman.
• Fornell, C., & Larcker, D. F. (1981). Evaluating structural equation models with unobservable variables and measurement error. Journal of Marketing Research, 18(1), 39–50. https://doi.org/10.1177/002224378101800104
• Haslam, N. (2006). Dehumanization: An integrative review. Personality and Social Psychology Review, 10(3), 252–264. https://doi.org/10.1207/s15327957pspr1003_4
• Lakoff, G., & Johnson, M. (1980). Metaphors we live by. University of Chicago Press.
• Nunnally, J. C., & Bernstein, I. H. (1994). Psychometric theory (3rd ed.). McGraw-Hill.
• Schwarzer, R., & Jerusalem, M. (1995). Generalized Self-Efficacy scale. In J. Weinman, S. Wright, & M. Johnston (Eds.), Measures in health psychology: A user’s portfolio. Causal and control beliefs (pp. 35–37). NFER-NELSON.
• Tangney, J. P., Baumeister, R. F., & Boone, A. L. (2004). High self-control predicts good adjustment, less pathology, better grades, and interpersonal success. Journal of Personality, 72(2), 271–324. https://doi.org/10.1111/j.0022-3506.2004.00263.x
• Weihrauch, A., & Huang, S. (2021). Portraying humans as machines to promote health: Unintended risks, mechanisms, and solutions. Journal of Marketing, 85(3), 184–203. https://doi.org/10.1177/0022242920974989

Items of the Scale