Journal of Preventive Medicine

Introduction
Over the last 30 years, the consumption of fast foods in the US and European countries has grown dramatically due to changes in people’s lifestyles. Fast foods are prepared quickly and easily and offered in restaurants and cafes as a snack. College students are in a critical period and age for establishing healthy behaviors. The theory of planned behavior (TPB) has been widely used in various studies to determine attitudes and beliefs related to food choices. This theory, in addition to individual factors, pays attention to social factors. Since no study on fast food consumption using the TPB has been conducted in Rafsanjan city so far, this study aims to determine the predictors of fast-food consumption based on the TPB among students of Rafsanjan University of Medical Sciences (RUMS).

Methods
This descriptive/analytical study was conducted on 350 students of RUMS in the academic year 2021-2022. According to the mean value and standard deviation specified in a similar study [1] for fast food consumption behavior (3.37±4.58) and considering d=0.05, the sample size was calculated and obtained 322. For more certainty, it increased to 350. Sampling was done by a stratified random method. Each faculty was considered as one stratum. The samples, according to the population and gender of each faculty, were randomly selected from the available 5 faculties. After explaining the objectives of the study to the students and obtaining their consent, a self-report questionnaire was given to them. This questionnaire had 4 parts; the first part was about demographic characteristics, the second part was about awareness, the third part included questions based on the TPB constructs, and the fourth part evaluated the amount of fast-food consumption in the past week. After collecting the data and entering them into SPSS software, version 16, they were analyzed using descriptive statistics (mean, standard deviation) and analytical tests, including Spearman’s correlation test, t-test, and ANOVA.

Results
The mean age of the participants was 21.06±2.51 years (ranged 18-38 years); 219 were female (62.6%) and 131 (37.4%) were male. Most of them (90%) were single and only 10% were married. Most of them were living in the dormitory (78.9%) and were from middle-income families (54.6%). Most of the students’ fathers (55.71%) and mothers (50.6%) had a university education. Moreover, most of the students reported that their families (77.7%) and friends (94.6%) had fast-food consumption. Also, 86% of students stated that they consumed fast food. The mean scores of knowledge and the TPB domains of positive attitude, positive subjective norm, perceived behavioral control, and positive behavioral intention were 17.77±3.90, 55.02±11.65, 8±3.69, 14.87±2.78 and 7.73±3.69, respectively. According to the mentioned variables’ scores, knowledge received the highest score (80.77% of total score). Based on the results of Spearman’s correlation test, it was found that fast-food consumption behavior had a significant positive correlation with the TPB domains of positive behavioral intention, positive subjective norm, and positive attitude, while had a significant negative correlation with knowledge and the TPB domain of perceived behavioral control (P<0.05). The results of linear regression showed that the TPB constructs predicted 7% of the variance in fast-food consumption behavior, where the positive subjective norm was the strongest predictor (B=0.241).

Discussion
The results of this study showed that the fast-food consumption behavior of RUMS students had a significant positive correlation with the TPB domains of positive behavioral intention, positive subjective norm, and positive attitude, while had a significant negative correlation with knowledge and the TPB domain of perceived behavioral control. It seems that in designing educational interventions for reducing fast food consumption among college students, it is better to pay attention to increasing students’ awareness and self-efficacy about not consuming fast foods, and try to weaken the positive attitude of the students and strengthen the negative attitudes towards fast foods so that their positive intention to consuming fast food can decrease. The positive subjective norm domain was the strongest predictor of fast-food consumption behavior in students. The pressure from peers seems to play an important role in the subjective norms encouraging fast food consumption. Increasing their courage and ability to say no to fast-food consumption should be started and institutionalized in students before entering the university by including nutrition lessons in the high school curriculum. In educational interventions, students should learn to resist peer pressure and express opposition.

Ethical Considerations
Compliance with ethical guidelines
This study was approved by the ethics committee of Rafsanjan University of Medical Sciences (Code: IR.RUMS.REC.1399.153).

Funding
This study was funded by Rafsanjan University of Medical Sciences.

Authors' contributions
Study design: Mohammad Asadpour, Mahmoud Mehboubi; data collection: Mohammad Mobini and Erfan Shahabinejad; data analysis: Mostafa Nasirzadeh; review & editing: All authors.

Conflicts of interest
The authors declared no conflict of interest.

Acknowledgements
The authors would like to thank the students participated in this study and the Vice-Chancellor for Research and Technology of Rafsanjan University of Medical Sciences for the financial support.

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