- Email: [email protected]
Psychometric evaluation of the power of food scale in a diverse college sample: Measurement invariance across gender, ethnicity, and weight status
Eating Behaviors 35 (2019) 101336
Contents lists available at ScienceDirect
Eating Behaviors journal homepage: www.elsevier.com/locate/eatbeh
Psychometric evaluation of the power of food scale in a diverse college sample: Measurement invariance across gender, ethnicity, and weight status
T
Kelsey N. Serier, Katherine E. Belon1, Jamie M. Smith, Jane Ellen Smith* University of New Mexico, Department of Psychology, MSC03 2220, Albuquerque, NM 87131, United States
ARTICLE INFO
ABSTRACT
Keywords: Power of food scale College students Measurement invariance Hedonic hunger Diverse sample
The Power of Food Scale (PFS) is an instrument designed to examine individual differences in the drive to eat for pleasure (as opposed to in response to physiological hunger) and the effect of living in an obesogenic environment. Previous research supports the validity and reliability of the PFS, however, it had yet to be validated in an ethnically diverse college sample. The purpose of the current study was to test the factor structure and measurement invariance of the PFS across gender, ethnicity, and weight status. A sample of 432 college students completed the PFS (males = 113, females = 319; non-Hispanic white = 181, Hispanic = 251; non-overweight = 302, overweight = 130). Confirmatory factor analysis was used to test a second-order, 3-factor (food available, food present, food tasted) structure of the PFS in each group separately (males, females, Hispanic, nonHispanic white, non-overweight, and overweight) and tests of measurement invariance were conducted to test the equivalency of the measure across gender, ethnicity, and weight status. Results supported the measure’s original factor structure (second-order, 3-factor model) and indicated that the measure is equivalent across each of these groups, respectively. Although the small, unbalanced groups may impact the stability of the findings, the results nonetheless suggest that the PFS is a psychometrically valid measure in a diverse college sample, and that mean comparisons on this measure are meaningful across gender, ethnicity, and weight status. Given the measurement invariance of the PFS, there is support for use of the PFS among diverse college students in future work.
1. Introduction The Power of Food Scale (PFS) is an instrument designed to measure individual differences in hedonic hunger; the drive to eat for pleasure purposes as opposed to in response to physiological hunger. The PFS also examines the psychological impact of being immersed in foodabundant environments (Cappelleri et al., 2009; Lowe et al., 2009). This instrument has been used in samples with varying ages, weight statuses, and nationalities, and generally has demonstrated adequate internal consistency, test-retest reliability, and incremental validity beyond what is accounted for by a measure of dietary restraint in predicting eating patterns (Aliasghari, Jafarabadi, Yaghin, & Mahdavi, 2018; Cappelleri et al., 2009; Lowe et al., 2009). The PFS is related to eating behaviors, such that higher aggregate PFS scores predict greater food cravings and increased consumption (Forman et al., 2007) and binge eating among women with eating disorders (Witt & Lowe, 2014) and overweight women (Manasse et al., 2015). A longitudinal study of a weight loss program for obese
individuals found that decreases in hedonic hunger were associated with weight loss (O’Neil, Theim, Boeka, Johnson, & Miller-Kovach, 2012). It is important to note that outside of such weight loss programs, past literature has generally found no or little relationship between hedonic hunger and Body Mass Index (BMI) or weight gain, suggesting that hedonic hunger is more strongly tied to eating behaviors and is present across BMI levels (Cappelleri et al., 2009; Espel‐Huynh, Muratore, & Lowe, 2018; Lipsky et al., 2016; Lowe et al., 2009; Vainik, Neseliler, Konstabel, Fellows, & Dagher, 2015). In summary, the PFS appears to be a reliable and valid measure of hedonic hunger and uniquely predicts certain eating behaviors. Previous research has examined the factor structure of the PFS. Consistent support has been found for a 15-item, second-order structure with items loading onto three factors: food available, food present, and food tasted (Cappelleri et al., 2009; Lowe et al., 2009, Mitchell, Cusching, & Amaro, 2016). A second-order structure indicates that the three latent factors (given high correlations between the factors) load onto a single latent factor, which represents an aggregate score.
Corresponding author. E-mail addresses: [email protected] (K.N. Serier), [email protected] (K.E. Belon), [email protected] (J.M. Smith), [email protected] (J.E. Smith). 1 Currently at the New Mexico Veterans Affairs Health Care System, 1501 San Pedro SE, Albuquerque, NM, 87108, United States. ⁎
https://doi.org/10.1016/j.eatbeh.2019.101336 Received 7 March 2019; Received in revised form 22 September 2019; Accepted 26 September 2019 Available online 25 October 2019 1471-0153/ © 2019 Elsevier Ltd. All rights reserved.
Eating Behaviors 35 (2019) 101336
K.N. Serier, et al.
Although previous research has examined the psychometric properties of the PFS in samples from other countries, little work has been done to examine the validity of the PFS in diverse college samples within the United States, particularly among students identifying as Hispanic/Latino(a). A study of the PFS in college students found support for a second-order, 3-factor structure. However, conclusions about this measure across different ethnicities and gender were unclear, as 67% of this sample was not asked about ethnicity and only 7% reported being male (Lowe et al., 2009). Other studies in college students investigating the relationship between the PFS and related constructs used predominantly female, non-Hispanic white samples (Hispanic participants ranged from 0 to 6%; Forman et al., 2007; Lowe et al., 2016; Witt, Raggio, Butryn, & Lowe, 2014). Calls have been made to validate the PFS in samples with greater ethnic diversity and higher proportions of men (Espel‐Huynh et al., 2018; Lowe et al., 2009), which is the aim of the current study. Additionally, there does not appear to be any work that has examined measurement invariance, or the comparability of scores, across ethnic identity in a college sample. Validating the PFS in a diverse sample of college students is necessary groundwork for future research that should examine the impact of individual differences in hedonic hunger.
30.1% (n = 130) with a BMI ≥ 25.0 [overweight]. The final sample had an average age of 21.39 years (SD = 5.58; range = 18–58). 3.2. Measures 3.2.1. Demographics A form collected data on age, gender, BMI, and ethnicity/race (National Institutes of Health, 2018; Office of Management & Budget, 1997). 3.2.2. Power of Food Scale (PFS; Lowe et al., 2009) This 15-item instrument measures hedonic hunger on a five-point Likert-type scale ranging from 1 (I don’t agree) to 5 (I strongly agree). The PFS has three subscales representing different levels of food proximity: food available (thoughts about food generally; “I find myself thinking about food even when I’m not physically hungry”), food present (a draw toward food directly available; “If I see or smell a food I like, I get a powerful urge to have some”), and food tasted (desire and liking of food at first taste; “When I eat delicious food I focus a lot on how good it tastes”). Acceptable internal consistency was demonstrated in college students, a clinical sample of obese individuals, and a nationally representative sample (Cappelleri et al., 2009; Lowe et al., 2009).
2. The current study
3.3. Data analysis
The current study aimed to examine the construct validity and measurement invariance of the PFS across gender, ethnicity, and weight status in a sample of Hispanic and non-Hispanic white college students. Measurement invariance tests whether the same construct is being measured across groups, and is an important step before comparing groups’ scores on a measure (Byrne, Shavelson, & Muthén, 1989). With respect to gender and weight status, we sought to replicate previous findings that found the PFS to be invariant across these constructs in an adult sample (Cappelleri et al., 2009). In addition to replicating previous work, the current study sought to extend the literature by testing measurement invariance of the PFS across non-Hispanic white and Hispanic college students. Findings examining measurement invariance of other eating-related measures across ethnically diverse college students have been mixed, with some studies finding invariance (Belon et al., 2011) and others finding a lack thereof (Belon et al., 2015; Serier, Smith, & Yeater, 2018). Tests of measurement invariance in the current study were largely exploratory in nature, yet given the wide access to highly palatable foods in the current environment, we hypothesized that the PFS would be invariant across ethnic identity. Furthermore, previous research found no evidence that relationships between scores on the PFS and other eating-related constructs (e.g., dieting, loss of control eating) differed as a function of race/ethnicity (Lipsky et al., 2016; Lowe et al., 2016).
All analyses were completed using SPSS Version 25 (IBM Corp., 2017) and Mplus Version 8 (Muthén & Muthén, 2017). There were no missing data to responses on the PFS. The PFS factor structure was examined using confirmatory factor analysis (CFA) with unit loading identification. Indicators were treated as categorical, and the weighted least squares estimator (WLSMV; Li, 2016) and the variance-covariance matrix were used to estimate the model. Model fit was examined using the Comparative Fit Index (CFI; cutoff = 0.90), Tucker-Lewis Index (TLI; cutoff = 0.90), root-mean-square error of approximation (RMSEA; cutoff = 0.08), and weighted root-mean-square residual (WRMR; cut-off = 0.90; Hu & Bentler, 1999; Yu, 2002). To determine whether the PFS was stable and equivalent across gender, ethnicity, and weight status, we conducted tests of measurement invariance. Measurement invariance fits increasingly restrictive models to the data. The least restrictive model, the configural model, holds the factor structure equal across groups. The metric model holds the factor structure and factor loadings equal across groups. The most restrictive model, the scalar model, holds the factor structure, factor loadings, and factor intercepts equal across groups. The chi-square difference test is used to examine if the added restrictions to the model make model fit significantly worse. A non-significant chi-square difference test indicates that the additional constraints do not make model fit significantly worse, and that the measure is invariant.
3. Materials and methods 3.1. Participants and procedures
4. Results
Students aged 18 or older were recruited from undergraduate psychology courses at the University of New Mexico. Students were provided with listings of available studies, and they enrolled in the ones of interest via a web-based system. Participants completed self-report measures as part of a larger study on eating patterns, and were compensated with course credit or extra credit. Altogether 490 participants completed the online survey. Ethnic/ racial groups with insufficient sample sizes were excluded due to our interest in measurement invariance analyses. The final sample size of 432 individuals was 73.8% (n = 319) female and 26.2% (n = 113) male. Over half the sample (58.1%) identified as being of Hispanic origin (n = 251) and 41.9% (n = 181) identified as non-Hispanic white. Weight status was divided into two groups, with 69.9% (n = 302) of the sample having a BMI < 25.0 [non-overweight] and
4.1. Descriptive statistics There were no significant differences on any of the PFS subscales across gender or ethnicity (Table 1). However, overweight participants scored significantly higher on the food available subscale relative to non-overweight participants, t (430) = 2.14, p = 0.03. 4.2. Internal consistency Cronbach’s alpha was acceptable across gender, ethnicity, and weight status. Internal consistency ranged from α = 0.87–0.90 on the food available subscale, α = 0.87–0.90 on the food present subscale, α = 0.83–0.85 on the food tasted subscale, and α = 0.93–0.94 on the aggregate scale. 2
Eating Behaviors 35 (2019) 101336
K.N. Serier, et al.
Table 1 Descriptive Statistics for the Power of Food Scale across Gender, Ethnicity, and Weight Status. Gender Power of Food Subscales Food Available Food Present Food Tasted Aggregate
Ethnicity
Male (n = 113) 1.91 ± 0.88 2.39 ± 1.12 2.44 ± 0.98 2.21 ± 0.89
Female (n = 319) 1.96 ± 0.93 2.51 ± 1.07 2.37 ± 0.92 2.24 ± 0.86
Weight Status
Non-Hispanic White (n = 181) 1.93 ± 0.94 2.39 ± 1.03 2.34 ± 0.93 2.19 ± 0.87
Hispanic (n = 251) 1.95 ± 0.90 2.54 ± 1.12 2.42 ± 0.94 2.27 ± 0.86
Non-overweight (n = 302) 1.88 ± 0.88* 2.43 ± 1.09 2.37 ± 0.93 2.19 ± 0.85
Overweight (n = 130) 2.09 ± 0.98* 2.60 ± 1.07 2.42 ± 0.95 2.33 ± 0.90
Note: * indicates significant group differences at p < .05.
4.3. Factor analysis and measurement invariance
weight status, indicating that the factor structure, loadings, and intercepts were equivalent across groups (Table 2).
The previously established second-order, 3-factor model (Cappelleri et al., 2009; Lowe et al., 2009) was fitted to the data for each gender, ethnic, and weight status group. This model was an acceptable fit in each group. Thus, the second-order, 3-factor model was used in tests of measurement invariance to examine the equivalence of this measure across groups. The non-significant difference tests indicated that the measure achieved scalar invariance across gender, ethnicity, and
5. Discussion Our results support the internal consistency and measurement invariance of the PFS across gender, ethnicity, and weight status within an ethnically diverse group of college students, thereby adding to findings that demonstrated measurement invariance relative to gender
Table 2 Fit Statistics, Standardized Factor Loadings, and Measurement Invariance of the Power of Food Scale (PFS) across Gender, Ethnicity, and Weight Status. Model Fit Statistics
df
χ2
CFI
TLI
RMSEA
WRMR
Male (n = 113) Female (n = 319) Non-Hispanic White (n = 181) Hispanic (n = 251) Non-overweight (n = 302) Overweight (n = 130)
87 87 87 87 87 87
170.77 322.45 218.82 263.85 280.51 186.94
0.97 0.97 0.97 0.97 0.97 0.97
0.96 0.96 0.96 0.96 0.97 0.96
0.09 0.09 0.09 0.09 0.09 0.09
0.78 1.02 0.86 0.96 0.98 0.79
Standardized Factor Loadings
Male (n = 113)
Female (n = 319)
Non-Hispanic White (n = 181)
Hispanic (n = 251)
Non-Overweight (n = 302)
Overweight (n = 130)
0.69 0.80 0.78 0.72 0.89 0.89
0.80 0.85 0.83 0.81 0.86 0.90
0.79 0.87 0.81 0.81 0.85 0.90
0.76 0.81 0.82 0.77 0.86 0.89
0.75 0.83 0.81 0.79 0.84 0.88
0.80 0.84 0.82 0.78 0.89 0.93
0.84 0.92 0.86 0.88
0.81 0.88 0.88 0.82
0.81 0.87 0.86 0.79
0.83 0.90 0.88 0.87
0.83 0.89 0.88 0.85
0.79 0.88 0.87 0.80
Food Available PFS 1 PFS 2 PFS 5 PFS 10 PFS 11 PFS 13 Food Present PFS 3 PFS 4 PFS 6 PFS 7 Food Tasted PFS 8 PFS 9 PFS 12 PFS 14 PFS 15 Aggregate Food Available Food Present Food Tasted
0.84 0.79 0.83 0.77 0.69
0.81 0.70 0.84 0.78 0.67
0.77 0.73 0.83 0.79 0.72
0.85 0.72 0.84 0.76 0.65
0.81 0.74 0.83 0.79 0.65
0.83 0.69 0.85 0.75 0.74
0.95 0.92 0.92
0.91 0.89 0.94
0.96 0.93 0.93
0.90 0.89 0.93
0.91 0.90 0.94
0.97 0.89 0.92
Measurement Invariance
df
χ2
df
Δ χ2
p value
CFI
TLI
RMSEA
WRMR
174 192 252
473.27 263.95 320.65
18 60
17.38 61.31
0.50 0.43
0.97 0.99 0.99
0.96 0.99 0.99
0.09 0.04 0.04
1.29 1.43 1.56
174 192 252
482.34 266.08 317.86
18 60
17.08 56.49
0.52 0.60
0.96 0.99 0.99
0.96 0.99 1.00
0.09 0.04 0.04
1.29 1.42 1.53
174 192 252
463.33 256.22 319.02
18 60
16.20 69.90
0.58 0.18
0.97 0.99 0.99
0.96 0.99 0.99
0.09 0.04 0.04
1.25 1.38 1.56
Gender Configural Metric Scalar Ethnicity Configural Metric Scalar Weight Status Configural Metric Scalar
Note: PFS = Power of Food Scale.
3
Eating Behaviors 35 (2019) 101336
K.N. Serier, et al.
and obesity among a middle-aged adult sample (Cappelleri et al., 2009). Consequently, there is now evidence to suggest that group differences in PFS scores are capturing actual differences in hedonic hunger among Hispanic and non-Hispanic white college students. Past studies of the PFS either failed to report ethnicity altogether or were conducted in predominantly non-Hispanic white samples (Cappelleri et al., 2009; Lowe et al., 2009). By demonstrating measurement invariance across ethnicity, the current study lays the foundation for understanding the relationship between culture and hedonic hunger. Furthermore, the PFS holds promise for identifying mechanisms underlying problematic eating patterns. The PFS captures individual differences in the rewarding properties of food, which may underlie individual differences in food cravings, loss of control eating, and/or binge eating (Forman et al., 2007; Lowe et al., 2016; Manasse et al., 2015; Witt & Lowe, 2014). With evidence of the psychometric validity of the PFS in a Hispanic college sample, future research will be able to explore how the PFS relates to eating behaviors taking into account intersectionality (e.g., weight status and ethnic identity) and/ or potentially relevant cultural variables (e.g., level of acculturation). Strengths of the current study include implementing advanced statistical techniques to examine methodological properties of the PFS in a sizeable ethnically diverse college sample. Limitations include the small and unbalanced groups, which may impact the stability of the findings. However, the fit statistics in the current study also met the more stringent requirements proposed by Chen (2007) for evaluating measurement invariance in small and unbalanced samples. Additionally, it is unclear how the findings from the current study would generalize to other racial/ethnic groups, non-college adult samples, groups with varying levels of acculturation, and across the lifespan. Future work should examine the psychometric properties of the PFS in other populations and examine measurement invariance across age, which was not examined in the current study given the limited age variability in the sample. In addition, the PFS should be examined in the context of food insecurity. The current study operated under the assumption that access to highly palatable foods was similar across groups in our cultural context. However, many college students face food insecurity (e.g., Gaines, Robb, Knol, & Sickler, 2014), which should be measured when drawing conclusions about patterns of eating behaviors.
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R., Butryn, M. L., Didie, E. R., Annunziato, R. A., Thomas, J. G., Crerand, C. E., et al. (2009). The Power of Food Scale. A new measure of the psychological influence of the food environment. Appetite, 53, 114–118. https://doi.org/10.1016/j.appet. 2009.05.016. Manasse, S. M., Espel, H. M., Forman, E. M., Ruocco, A. C., Juarascio, A. S., Butryn, M. L., et al. (2015). The independent and interacting effects of hedonic hunger and executive function on binge eating. Appetite, 89, 16–21. https://doi.org/10.1016/j. appet.2016.01.013. Mitchell, T. B., Cushing, C. C., & Amaro, C. M. (2016). Psychometric properties of the power of food scale in a community sample of preadolescents and adolescents. Journal of Child and Family Studies, 25, 2733–2739. https://doi.org/10.1007/s10826016-0444-3. Muthén, L. K., & Muthén, B. O. (2017). Mplus user’s guide: Statistical analysis with latent variables: User’s guide. Muthén: Muthén &. National Institutes of Health (2018). Frequently asked questions. 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6. Conclusion The current study provides additional support for a 3-factor, 15item, second-order factor structure of the PFS. The study also found support for measurement invariance of the PFS across gender, ethnicity, and weight status in a sample of college students. The PFS appears to be a reliable and valid measure of hedonic hunger in Hispanic college students. References Aliasghari, F., Jafarabadi, M. A., Yaghin, N. L., & Mahdavi, R. (2018). Psychometric properties of power of food scale in Iranian adult population: Gender-related differences in hedonic hunger. Eating and Weight Disorders-Studies on Anorexia, Bulimia and Obesity, 1–9. https://doi.org/10.1007/s40519-018-0549-3. Belon, K. E., Smith, J. E., Bryan, A. D., Lash, D. N., Winn, J. L., & Gianini, L. M. (2011). Measurement invariance of the eating attitudes test-26 in Caucasian and Hispanic women. Eating Behaviors, 12, 317–320. https://doi.org/10.1016/j.eatbeh.2011.07. 007. Belon, K. E., McLaughlin, E. A., Smith, J. E., Bryan, A. D., Witkiewitz, K., Lash, D. N., et al. (2015). Testing the measurement invariance of the eating disorder inventory in nonclinical samples of Hispanic and Caucasian women. International Journal of Eating
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Contents lists available at ScienceDirect
Eating Behaviors journal homepage: www.elsevier.com/locate/eatbeh
Psychometric evaluation of the power of food scale in a diverse college sample: Measurement invariance across gender, ethnicity, and weight status
T
Kelsey N. Serier, Katherine E. Belon1, Jamie M. Smith, Jane Ellen Smith* University of New Mexico, Department of Psychology, MSC03 2220, Albuquerque, NM 87131, United States
ARTICLE INFO
ABSTRACT
Keywords: Power of food scale College students Measurement invariance Hedonic hunger Diverse sample
The Power of Food Scale (PFS) is an instrument designed to examine individual differences in the drive to eat for pleasure (as opposed to in response to physiological hunger) and the effect of living in an obesogenic environment. Previous research supports the validity and reliability of the PFS, however, it had yet to be validated in an ethnically diverse college sample. The purpose of the current study was to test the factor structure and measurement invariance of the PFS across gender, ethnicity, and weight status. A sample of 432 college students completed the PFS (males = 113, females = 319; non-Hispanic white = 181, Hispanic = 251; non-overweight = 302, overweight = 130). Confirmatory factor analysis was used to test a second-order, 3-factor (food available, food present, food tasted) structure of the PFS in each group separately (males, females, Hispanic, nonHispanic white, non-overweight, and overweight) and tests of measurement invariance were conducted to test the equivalency of the measure across gender, ethnicity, and weight status. Results supported the measure’s original factor structure (second-order, 3-factor model) and indicated that the measure is equivalent across each of these groups, respectively. Although the small, unbalanced groups may impact the stability of the findings, the results nonetheless suggest that the PFS is a psychometrically valid measure in a diverse college sample, and that mean comparisons on this measure are meaningful across gender, ethnicity, and weight status. Given the measurement invariance of the PFS, there is support for use of the PFS among diverse college students in future work.
1. Introduction The Power of Food Scale (PFS) is an instrument designed to measure individual differences in hedonic hunger; the drive to eat for pleasure purposes as opposed to in response to physiological hunger. The PFS also examines the psychological impact of being immersed in foodabundant environments (Cappelleri et al., 2009; Lowe et al., 2009). This instrument has been used in samples with varying ages, weight statuses, and nationalities, and generally has demonstrated adequate internal consistency, test-retest reliability, and incremental validity beyond what is accounted for by a measure of dietary restraint in predicting eating patterns (Aliasghari, Jafarabadi, Yaghin, & Mahdavi, 2018; Cappelleri et al., 2009; Lowe et al., 2009). The PFS is related to eating behaviors, such that higher aggregate PFS scores predict greater food cravings and increased consumption (Forman et al., 2007) and binge eating among women with eating disorders (Witt & Lowe, 2014) and overweight women (Manasse et al., 2015). A longitudinal study of a weight loss program for obese
individuals found that decreases in hedonic hunger were associated with weight loss (O’Neil, Theim, Boeka, Johnson, & Miller-Kovach, 2012). It is important to note that outside of such weight loss programs, past literature has generally found no or little relationship between hedonic hunger and Body Mass Index (BMI) or weight gain, suggesting that hedonic hunger is more strongly tied to eating behaviors and is present across BMI levels (Cappelleri et al., 2009; Espel‐Huynh, Muratore, & Lowe, 2018; Lipsky et al., 2016; Lowe et al., 2009; Vainik, Neseliler, Konstabel, Fellows, & Dagher, 2015). In summary, the PFS appears to be a reliable and valid measure of hedonic hunger and uniquely predicts certain eating behaviors. Previous research has examined the factor structure of the PFS. Consistent support has been found for a 15-item, second-order structure with items loading onto three factors: food available, food present, and food tasted (Cappelleri et al., 2009; Lowe et al., 2009, Mitchell, Cusching, & Amaro, 2016). A second-order structure indicates that the three latent factors (given high correlations between the factors) load onto a single latent factor, which represents an aggregate score.
Corresponding author. E-mail addresses: [email protected] (K.N. Serier), [email protected] (K.E. Belon), [email protected] (J.M. Smith), [email protected] (J.E. Smith). 1 Currently at the New Mexico Veterans Affairs Health Care System, 1501 San Pedro SE, Albuquerque, NM, 87108, United States. ⁎
https://doi.org/10.1016/j.eatbeh.2019.101336 Received 7 March 2019; Received in revised form 22 September 2019; Accepted 26 September 2019 Available online 25 October 2019 1471-0153/ © 2019 Elsevier Ltd. All rights reserved.
Eating Behaviors 35 (2019) 101336
K.N. Serier, et al.
Although previous research has examined the psychometric properties of the PFS in samples from other countries, little work has been done to examine the validity of the PFS in diverse college samples within the United States, particularly among students identifying as Hispanic/Latino(a). A study of the PFS in college students found support for a second-order, 3-factor structure. However, conclusions about this measure across different ethnicities and gender were unclear, as 67% of this sample was not asked about ethnicity and only 7% reported being male (Lowe et al., 2009). Other studies in college students investigating the relationship between the PFS and related constructs used predominantly female, non-Hispanic white samples (Hispanic participants ranged from 0 to 6%; Forman et al., 2007; Lowe et al., 2016; Witt, Raggio, Butryn, & Lowe, 2014). Calls have been made to validate the PFS in samples with greater ethnic diversity and higher proportions of men (Espel‐Huynh et al., 2018; Lowe et al., 2009), which is the aim of the current study. Additionally, there does not appear to be any work that has examined measurement invariance, or the comparability of scores, across ethnic identity in a college sample. Validating the PFS in a diverse sample of college students is necessary groundwork for future research that should examine the impact of individual differences in hedonic hunger.
30.1% (n = 130) with a BMI ≥ 25.0 [overweight]. The final sample had an average age of 21.39 years (SD = 5.58; range = 18–58). 3.2. Measures 3.2.1. Demographics A form collected data on age, gender, BMI, and ethnicity/race (National Institutes of Health, 2018; Office of Management & Budget, 1997). 3.2.2. Power of Food Scale (PFS; Lowe et al., 2009) This 15-item instrument measures hedonic hunger on a five-point Likert-type scale ranging from 1 (I don’t agree) to 5 (I strongly agree). The PFS has three subscales representing different levels of food proximity: food available (thoughts about food generally; “I find myself thinking about food even when I’m not physically hungry”), food present (a draw toward food directly available; “If I see or smell a food I like, I get a powerful urge to have some”), and food tasted (desire and liking of food at first taste; “When I eat delicious food I focus a lot on how good it tastes”). Acceptable internal consistency was demonstrated in college students, a clinical sample of obese individuals, and a nationally representative sample (Cappelleri et al., 2009; Lowe et al., 2009).
2. The current study
3.3. Data analysis
The current study aimed to examine the construct validity and measurement invariance of the PFS across gender, ethnicity, and weight status in a sample of Hispanic and non-Hispanic white college students. Measurement invariance tests whether the same construct is being measured across groups, and is an important step before comparing groups’ scores on a measure (Byrne, Shavelson, & Muthén, 1989). With respect to gender and weight status, we sought to replicate previous findings that found the PFS to be invariant across these constructs in an adult sample (Cappelleri et al., 2009). In addition to replicating previous work, the current study sought to extend the literature by testing measurement invariance of the PFS across non-Hispanic white and Hispanic college students. Findings examining measurement invariance of other eating-related measures across ethnically diverse college students have been mixed, with some studies finding invariance (Belon et al., 2011) and others finding a lack thereof (Belon et al., 2015; Serier, Smith, & Yeater, 2018). Tests of measurement invariance in the current study were largely exploratory in nature, yet given the wide access to highly palatable foods in the current environment, we hypothesized that the PFS would be invariant across ethnic identity. Furthermore, previous research found no evidence that relationships between scores on the PFS and other eating-related constructs (e.g., dieting, loss of control eating) differed as a function of race/ethnicity (Lipsky et al., 2016; Lowe et al., 2016).
All analyses were completed using SPSS Version 25 (IBM Corp., 2017) and Mplus Version 8 (Muthén & Muthén, 2017). There were no missing data to responses on the PFS. The PFS factor structure was examined using confirmatory factor analysis (CFA) with unit loading identification. Indicators were treated as categorical, and the weighted least squares estimator (WLSMV; Li, 2016) and the variance-covariance matrix were used to estimate the model. Model fit was examined using the Comparative Fit Index (CFI; cutoff = 0.90), Tucker-Lewis Index (TLI; cutoff = 0.90), root-mean-square error of approximation (RMSEA; cutoff = 0.08), and weighted root-mean-square residual (WRMR; cut-off = 0.90; Hu & Bentler, 1999; Yu, 2002). To determine whether the PFS was stable and equivalent across gender, ethnicity, and weight status, we conducted tests of measurement invariance. Measurement invariance fits increasingly restrictive models to the data. The least restrictive model, the configural model, holds the factor structure equal across groups. The metric model holds the factor structure and factor loadings equal across groups. The most restrictive model, the scalar model, holds the factor structure, factor loadings, and factor intercepts equal across groups. The chi-square difference test is used to examine if the added restrictions to the model make model fit significantly worse. A non-significant chi-square difference test indicates that the additional constraints do not make model fit significantly worse, and that the measure is invariant.
3. Materials and methods 3.1. Participants and procedures
4. Results
Students aged 18 or older were recruited from undergraduate psychology courses at the University of New Mexico. Students were provided with listings of available studies, and they enrolled in the ones of interest via a web-based system. Participants completed self-report measures as part of a larger study on eating patterns, and were compensated with course credit or extra credit. Altogether 490 participants completed the online survey. Ethnic/ racial groups with insufficient sample sizes were excluded due to our interest in measurement invariance analyses. The final sample size of 432 individuals was 73.8% (n = 319) female and 26.2% (n = 113) male. Over half the sample (58.1%) identified as being of Hispanic origin (n = 251) and 41.9% (n = 181) identified as non-Hispanic white. Weight status was divided into two groups, with 69.9% (n = 302) of the sample having a BMI < 25.0 [non-overweight] and
4.1. Descriptive statistics There were no significant differences on any of the PFS subscales across gender or ethnicity (Table 1). However, overweight participants scored significantly higher on the food available subscale relative to non-overweight participants, t (430) = 2.14, p = 0.03. 4.2. Internal consistency Cronbach’s alpha was acceptable across gender, ethnicity, and weight status. Internal consistency ranged from α = 0.87–0.90 on the food available subscale, α = 0.87–0.90 on the food present subscale, α = 0.83–0.85 on the food tasted subscale, and α = 0.93–0.94 on the aggregate scale. 2
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Table 1 Descriptive Statistics for the Power of Food Scale across Gender, Ethnicity, and Weight Status. Gender Power of Food Subscales Food Available Food Present Food Tasted Aggregate
Ethnicity
Male (n = 113) 1.91 ± 0.88 2.39 ± 1.12 2.44 ± 0.98 2.21 ± 0.89
Female (n = 319) 1.96 ± 0.93 2.51 ± 1.07 2.37 ± 0.92 2.24 ± 0.86
Weight Status
Non-Hispanic White (n = 181) 1.93 ± 0.94 2.39 ± 1.03 2.34 ± 0.93 2.19 ± 0.87
Hispanic (n = 251) 1.95 ± 0.90 2.54 ± 1.12 2.42 ± 0.94 2.27 ± 0.86
Non-overweight (n = 302) 1.88 ± 0.88* 2.43 ± 1.09 2.37 ± 0.93 2.19 ± 0.85
Overweight (n = 130) 2.09 ± 0.98* 2.60 ± 1.07 2.42 ± 0.95 2.33 ± 0.90
Note: * indicates significant group differences at p < .05.
4.3. Factor analysis and measurement invariance
weight status, indicating that the factor structure, loadings, and intercepts were equivalent across groups (Table 2).
The previously established second-order, 3-factor model (Cappelleri et al., 2009; Lowe et al., 2009) was fitted to the data for each gender, ethnic, and weight status group. This model was an acceptable fit in each group. Thus, the second-order, 3-factor model was used in tests of measurement invariance to examine the equivalence of this measure across groups. The non-significant difference tests indicated that the measure achieved scalar invariance across gender, ethnicity, and
5. Discussion Our results support the internal consistency and measurement invariance of the PFS across gender, ethnicity, and weight status within an ethnically diverse group of college students, thereby adding to findings that demonstrated measurement invariance relative to gender
Table 2 Fit Statistics, Standardized Factor Loadings, and Measurement Invariance of the Power of Food Scale (PFS) across Gender, Ethnicity, and Weight Status. Model Fit Statistics
df
χ2
CFI
TLI
RMSEA
WRMR
Male (n = 113) Female (n = 319) Non-Hispanic White (n = 181) Hispanic (n = 251) Non-overweight (n = 302) Overweight (n = 130)
87 87 87 87 87 87
170.77 322.45 218.82 263.85 280.51 186.94
0.97 0.97 0.97 0.97 0.97 0.97
0.96 0.96 0.96 0.96 0.97 0.96
0.09 0.09 0.09 0.09 0.09 0.09
0.78 1.02 0.86 0.96 0.98 0.79
Standardized Factor Loadings
Male (n = 113)
Female (n = 319)
Non-Hispanic White (n = 181)
Hispanic (n = 251)
Non-Overweight (n = 302)
Overweight (n = 130)
0.69 0.80 0.78 0.72 0.89 0.89
0.80 0.85 0.83 0.81 0.86 0.90
0.79 0.87 0.81 0.81 0.85 0.90
0.76 0.81 0.82 0.77 0.86 0.89
0.75 0.83 0.81 0.79 0.84 0.88
0.80 0.84 0.82 0.78 0.89 0.93
0.84 0.92 0.86 0.88
0.81 0.88 0.88 0.82
0.81 0.87 0.86 0.79
0.83 0.90 0.88 0.87
0.83 0.89 0.88 0.85
0.79 0.88 0.87 0.80
Food Available PFS 1 PFS 2 PFS 5 PFS 10 PFS 11 PFS 13 Food Present PFS 3 PFS 4 PFS 6 PFS 7 Food Tasted PFS 8 PFS 9 PFS 12 PFS 14 PFS 15 Aggregate Food Available Food Present Food Tasted
0.84 0.79 0.83 0.77 0.69
0.81 0.70 0.84 0.78 0.67
0.77 0.73 0.83 0.79 0.72
0.85 0.72 0.84 0.76 0.65
0.81 0.74 0.83 0.79 0.65
0.83 0.69 0.85 0.75 0.74
0.95 0.92 0.92
0.91 0.89 0.94
0.96 0.93 0.93
0.90 0.89 0.93
0.91 0.90 0.94
0.97 0.89 0.92
Measurement Invariance
df
χ2
df
Δ χ2
p value
CFI
TLI
RMSEA
WRMR
174 192 252
473.27 263.95 320.65
18 60
17.38 61.31
0.50 0.43
0.97 0.99 0.99
0.96 0.99 0.99
0.09 0.04 0.04
1.29 1.43 1.56
174 192 252
482.34 266.08 317.86
18 60
17.08 56.49
0.52 0.60
0.96 0.99 0.99
0.96 0.99 1.00
0.09 0.04 0.04
1.29 1.42 1.53
174 192 252
463.33 256.22 319.02
18 60
16.20 69.90
0.58 0.18
0.97 0.99 0.99
0.96 0.99 0.99
0.09 0.04 0.04
1.25 1.38 1.56
Gender Configural Metric Scalar Ethnicity Configural Metric Scalar Weight Status Configural Metric Scalar
Note: PFS = Power of Food Scale.
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and obesity among a middle-aged adult sample (Cappelleri et al., 2009). Consequently, there is now evidence to suggest that group differences in PFS scores are capturing actual differences in hedonic hunger among Hispanic and non-Hispanic white college students. Past studies of the PFS either failed to report ethnicity altogether or were conducted in predominantly non-Hispanic white samples (Cappelleri et al., 2009; Lowe et al., 2009). By demonstrating measurement invariance across ethnicity, the current study lays the foundation for understanding the relationship between culture and hedonic hunger. Furthermore, the PFS holds promise for identifying mechanisms underlying problematic eating patterns. The PFS captures individual differences in the rewarding properties of food, which may underlie individual differences in food cravings, loss of control eating, and/or binge eating (Forman et al., 2007; Lowe et al., 2016; Manasse et al., 2015; Witt & Lowe, 2014). With evidence of the psychometric validity of the PFS in a Hispanic college sample, future research will be able to explore how the PFS relates to eating behaviors taking into account intersectionality (e.g., weight status and ethnic identity) and/ or potentially relevant cultural variables (e.g., level of acculturation). Strengths of the current study include implementing advanced statistical techniques to examine methodological properties of the PFS in a sizeable ethnically diverse college sample. Limitations include the small and unbalanced groups, which may impact the stability of the findings. However, the fit statistics in the current study also met the more stringent requirements proposed by Chen (2007) for evaluating measurement invariance in small and unbalanced samples. Additionally, it is unclear how the findings from the current study would generalize to other racial/ethnic groups, non-college adult samples, groups with varying levels of acculturation, and across the lifespan. Future work should examine the psychometric properties of the PFS in other populations and examine measurement invariance across age, which was not examined in the current study given the limited age variability in the sample. In addition, the PFS should be examined in the context of food insecurity. The current study operated under the assumption that access to highly palatable foods was similar across groups in our cultural context. However, many college students face food insecurity (e.g., Gaines, Robb, Knol, & Sickler, 2014), which should be measured when drawing conclusions about patterns of eating behaviors.
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6. Conclusion The current study provides additional support for a 3-factor, 15item, second-order factor structure of the PFS. The study also found support for measurement invariance of the PFS across gender, ethnicity, and weight status in a sample of college students. The PFS appears to be a reliable and valid measure of hedonic hunger in Hispanic college students. References Aliasghari, F., Jafarabadi, M. A., Yaghin, N. L., & Mahdavi, R. (2018). Psychometric properties of power of food scale in Iranian adult population: Gender-related differences in hedonic hunger. Eating and Weight Disorders-Studies on Anorexia, Bulimia and Obesity, 1–9. https://doi.org/10.1007/s40519-018-0549-3. Belon, K. E., Smith, J. E., Bryan, A. D., Lash, D. N., Winn, J. L., & Gianini, L. M. (2011). Measurement invariance of the eating attitudes test-26 in Caucasian and Hispanic women. Eating Behaviors, 12, 317–320. https://doi.org/10.1016/j.eatbeh.2011.07. 007. Belon, K. E., McLaughlin, E. A., Smith, J. E., Bryan, A. D., Witkiewitz, K., Lash, D. N., et al. (2015). Testing the measurement invariance of the eating disorder inventory in nonclinical samples of Hispanic and Caucasian women. International Journal of Eating
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