Research
Reliability and validity of brief psychosocial measures related to dietary behaviors
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* Corresponding author: Gregory J Norman gnorman@ucsd.edu
1 Department of Family and Preventive Medicine, University of California, San Diego, 9500 Gilman Drive Dept 0811 La Jolla, CA 92093, USA
2 Graduate School of Public Health, San Diego State University, San Diego, CA USA
3 Department of Psychology, San Diego State University, San Diego, CA USA
International Journal of Behavioral Nutrition and Physical Activity 2010, 7:56 doi:10.1186/1479-5868-7-56
Published: 2 July 2010Abstract
Background
Measures of psychosocial constructs are required to assess dietary interventions. This study evaluated brief psychosocial scales related to 4 dietary behaviors (consumption of fat, fiber/whole grains, fruits, and vegetables).
Methods
Two studies were conducted. Study 1 assessed two-week reliability of the psychosocial measures with a sample of 49 college students. Study 2 assessed convergent and discriminant validity of the psychosocial measures with dietary nutrient estimates from a Food Frequency Questionnaire on 441 men and 401 women enrolled in an Internet-based weight loss intervention study.
Results
Study 1 test-retest reliability ICCs were strong and ranged from .63 to .79. In study 2, dietary fat cons, fiber/whole grain cons and self-efficacy, fruit and vegetable cons and self-efficacy, and healthy eating social support, environmental factors, enjoyment, and change strategies demonstrated adequate correlations with the corresponding dietary nutrient estimates.
Conclusions
Brief psychosocial measures related to dietary behaviors demonstrated adequate reliability and in most cases validity. The strongest and most consistent scales related to dietary behaviors were healthy eating change strategies and enjoyment. Consistent convergent validity was also found for the cons of change scales. These measures can be used in intervention studies to evaluate psychosocial mediators of dietary change in overweight and obese individuals.