Evaluating the Power of Food Scale in obese subjects and a general sample of individuals: development and measurement properties.
BACKGROUND
The Power of Food Scale (PFS) was developed to assess the psychological impact of today's food-abundant environments.


OBJECTIVE
To evaluate the structure of the PFS in diverse populations of obese and nonobese individuals.


METHODS
Data were obtained from obese adults in a clinical trial for a weight management drug (n=1741), and overweight, obese and normal weight adults in a Web-based survey (n=1275). Exploratory and confirmatory factor analyses were used to investigate the PFS structure using the clinical data. The model developed was then tested using the Web-based data. Relationships between PFS domains and body mass index (BMI) were examined. Logistic regression was used in the Web-based survey to evaluate the association between obesity status and PFS scores.


RESULTS
Clinical data indicated that the scale was best represented by a 15-item version with three subscale domains and an aggregate domain (average of three domains); this was confirmed with data from the Web-based survey (Comparative Fit Index: 0.95 and 0.94 for the clinical and Web-based studies, respectively). Cronbach's alpha for both data sets was high, ranging from 0.81 to 0.91. The relationships between BMI and each domain were weak (and approximately linear). A full category increase in PFS domain score (range 1-5) increased the odds of being obese 1.6-2.3 times.


CONCLUSIONS
The 15-item PFS is best represented by three domains and an aggregate domain. The PFS may provide a useful tool to evaluate the effects of obesity treatments on feelings of being controlled by food in an obesogenic food environment.
Cappelleri
J C
JC
Global Research and Development, Pfizer Inc., New London, CT 06320, USA. joseph.c.cappeller@pfizer.com
Bushmakin
A G
AG
Gerber
R A
RA
Leidy
N K
NK
Sexton
C C
CC
Karlsson
J
J
Lowe
M R
MR
D000465:Algorithms; D015992:Body Mass Index; D005163:Factor Analysis, Statistical; D005247:Feeding Behavior / Q000523:psychology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000523:psychology*; D011594:Psychometrics; D012307:Risk Factors; D011795:Surveys and Questionnaires; D014481:United States