Over the past two decades changes in lifestyle have considerably changed food consumption patterns. One of the most prominent trends is the increase in fast food consumption (Alsabieh et al., 2019; Krieger, Chan, Saelens, Solet, & Fleming, 2013; Schröder, Fito & Covas. 2007; Bowman & Vinyard, 2004). Fast foods are quick to prepare, easy to access, moderately inexpensive, and favored by individuals of most age groups (Askari, Solhi, & Montazeri, 2016). Fast food consumption may have immediate and lasting harmful effects on the health of children. Scientific evidence shows that children who eat fast food have a higher intake of energy, fat, saturated fat, sodium, carbonated soft drinks, and a lower intake of vitamins A and C, milk, fruit, and vegetables compared to those who do not (World Health Organization, 2017; ALFaris, Al-Tamimi, Al-Jobair, & Al-Shwaiyat, 2015; Paerataku, Ferdinand, Champagne, Ryan, & Bray, 2003; Timperio, Ball, Roberts, Andrianopoulos, & Crawford, 2009).
According to recent studies, the highest consumers of fast food are adolescents and children. Nearly one-third of these young aged children, use ready-made foods on a daily basis (Bowman, Gortmaker, Ebbeling, Pereira, & Ludwig, 2004; Paeratakul, Ferdinand, Champagne, Ryan, & Bray, 2003). Consistent with the global interest in fast foods, recent studies have shown that fast food consumption is rapidly increasing in Iran. For example, in two separate studies conducted in two large cities of Iran, Tehran, and Isfahan, scientists found that fast food consumption is remarkably growing among high school students (Ghaffari, Sherizadeh, Rakhshandehroo, & Ramezankhani, 2015; Yarmohammadi, Sharifirad, Azadbakht, Morovati Sharifabad, & Hassanzadeh, 2011). Increase of the consumption of high-energy and unhealthy foods (i.e., high sugar content drinks and fast food) has been linked to diabetes, hypertension (Seo, Lee, & Nam, 2011), greater cardiometabolic risk (Davies, Richardson & Stevenson, 2017) becoming overweight and/or obesity (Babbey, Jones, Yu, & Goldstein, 2009; Gibson, 2008; Malik, Schulze, & Hu, 2006; Rosenheck, 2008). Obesity as the popular outcome of fast food consumption is affecting more than half a billion individuals around the world (Bhurosy & Jeewson, 2014). Global statistics show that over 340 million children and adolescents aged 5–19 were overweight or obese in 2016 (World Health Organization, 2018). A similar study amongst an Iranian sample ages 12 to 17 revealed that 51% of children consume fast foods in the form of prepackaged snacks, packaged juice and soda, weekly (Dehdari & Mergen, 2012). In addition, a similar study on an Iranian sample found that 20% of adolescents and 10% of adults consumed sandwiches as a fast food at least three times a week (Faghih & Anousheh, 2008). Students who compose a significant percentage of the population are highly vulnerable to physical, psychological and social detriments, and desirable nutrition is a prerequisite for maintaining their health (Ghaffari et al., 2015).
Young adulthood is a critical time for developing healthy behaviors, as habits formed during this time tend to persist throughout life (Hammar, 2017). It has been suggested that changing eating habits may be done through changing attitudes towards them (Ogdan, Karim, choudry, & brown, 2007). With further research needed for understanding the link between attitudes and eating behaviors, there is a reliance on theories to provide substantial guidance for creating healthy behaviors (Ghaffari, Esfahani, Rakhshanderou, Hosseini koukamari, 2018; Davis, Campbell, Hildon, Hobbs, Michie, 2015). The Theory of Planned Behavior (TPB) developed by Ajzen and Fishbein (1980) has been widely used to examine the attitudes and beliefs associated with food choices. TPB predicts the occurrence of a specific behavior that an individual tends to engage in. In fact, TPB assumes that human behaviors are determined by behavioral intention to consume fast food affected by attitude, subjective norms, and perceived behavioral control. In relation to fast food use, the attitude would be the personal positive/negative feelings about the consumption of fast food. Subjective norms would be the degree to which an individual desires to respect and follow the opinions of individuals who are important to him or her. Perceived behavioral control would be an individuals perceived capabilities and beliefs in the use or disuse of fast food in a given environment (HS, Lee, & Nam, 2011). Several studies have applied this theory to explain how eating habits and behaviors are formed (Ajzen & Madden, 1986; Dunn, Mohr, Wilson, & Wittert, 2011; Kassem, Lee, Modeste, & Johnston, 2003; Maddock, Silbanuz, & Reger-Nash, 2008; Peng, 2009, Sharifirad, et al, 2011; Chitsaz, Javadi, Lin, Pakpour, 2017) and it has been successfully applied across a wide range of age groups (De Bruijn, Kroeze, Oenema, & Brug, 2008). Thus, we attempt to change the nutritional beliefs and behaviors of students, by reducing fast food consumption, through designing and testing an experimental intervention, in turn, preventing the prevalence of obesity and associated diseases. As such, the main hypotheses of this study are:
Hypothsis 1. There will be a significant reduction in fast food consumption between intervention and control groups in posttest
Hypothsis 2. There will be a significant reduction in fast food consumption of students between intervention and control groups in follow-up