Document Type : Research articles


1 PhD Candidate in Health Education and Health Promotion, Faculty of Health, Tehran University of Medical Sciences, Tehran, Iran

2 Associate Professor, Department of Health Education and Promotion, Faculty of Health, Tehran University of Medical Sciences, Tehran, Iran

3 Assistant Professor, Department of Epidemiology and Biostatistics, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran

4 Associate Professor, Health Education and Promotion Research Group, Health Metrics Research Center, Iranian Institute for Health Sciences Research, ACECR, Tehran, Iran

5 Associate Professor, Department of Nutrition and Biochemistry, School of Nutritional Sciences and Dietetics, Tehran university of Medical Sciences, Tehran, Iran


Background: The number of reported food illnesses in Iran has increased over the past 10 years.
Objectives: The present study aimed at investigating the effect of education, based on the transtheoretical model (TTM) and the theory of planned behaviour (subjective norm and perceived behavioural control), on reducing fast food consumption in obese Iranian female adolescents.
Methods: In this quasi-experimental study, data were collected through a survey. This study included 420 obese Iranian female adolescents, aged 15 to 18 years, who were gathered from 12 schools in city of Sabzevar in Iran during 2014 tand 2016. Using a questionnaire, the demographic and anthropometric characteristics, transtheoretical model (TTM) constructs, subjective norm, and
perceived behavioural control were measured and analysed.
Results: The average rates of perceived behavioral control (11.949±2.876), subjective norms (16.515±4.877), stages of change (6.355 ± 1.342), processes of change (8.614 ± 3.406), and self-efficacy (22.447 ± 6.783) in the education group were meaningfully increased (P value < 0.05); however, these changes were not meaningful in the control group (P value > 0.05). Also, no statistically meaningful difference was obtained in decisional balance between the 2 groups after the intervention (P = 0/924).
Conclusions: The results of this study suggest that the use of TTM (except with decisional balance) focuses on the perceived behavioural control, and subjective norms can be used in educational interventions and have useful results.