Characteristics of the studies, such as study design and duration, as well as the participants’ characteristics in terms of age, gender, sample size and school characteristics, are provided in Table 1.

As illustrated in Table 1, six studies were conducted in Saudi Arabia [35, 37, 39, 41, 44, 45], two in Kuwait [36, 43], and one each in Qatar [38], the UAE [40] and Oman [42]. All included studies were published between 2017 and 2022 except the one by Shama and Abdou [42] in Oman, which was published in 2009. Out of the eleven studies, six were randomised controlled trials [35,36,37, 39, 41, 43], four were pre-post studies [38, 40, 44, 45] and one used a static group comparison design [42]. Six studies were purely quantitative [35, 39,40,41,42, 45], and two adopted a mixed methods design [43, 44].

The sample sizes ranged from 28 in an RCT [35] to 3,967 participants across two schools in a pre-post study [40]. The age of the participants ranged from five to nineteen years. In six studies, the study participants were girls only [35, 37, 39, 43,44,45], while four studies had male and female students [36, 38, 40, 42] and one study had only male participants [41]. In six studies, the participants were students from intermediate and/or secondary schools [35, 37, 39, 42,43,44], two studies had primary school students [36, 38], one had students from primary, intermediate, and secondary schools [41], while the school education stage was not clearly reported in two studies [40, 45]. The number of schools participating in the studies ranged from one [38, 43,44,45] to thirty [42]. The interventions were either only conducted at public schools [36,37,38,39, 43,44,45], only at private schools [40], at public and private schools [36], while two studies did not report the school type [41, 42]. The study in Oman by Shama and Abdou [42] compared conventional schools with health-promoting schools, which have three main components: health education, health services, and a healthy environment. Intervention components and outcomes of the included eleven studies are detailed in Table 2.

The intervention duration ranged between one month [35] and one year [42]. However, it was not clearly reported in one study [44] and not reported at all in another study [36]. To change participants’ behaviour as per the BCW, intervention components in our systematic review were reported under nine intervention functions, including education; persuasion; incentivisation; coercion; training; enablement; modelling; environmental restructuring; and restrictions.

Participants in all included studies [35,36,37,38,39,40,41, 43,44,45] were educated on various topics related to nutrition, physical activity, or health, including the study by Shama and Abdou [42], where health education was a component of the health-promoting schools initiative. Different methods of educational interventions were implemented by providing factual nutritional information and advice (e.g. nutritional posters and cards, recipe cards) to the students and their families [38], instructions for changing nutritional and physical activity behaviours (e.g. increasing fruit and vegetable intake and reducing the intake of sugar sweetened beverages, receiving information about the function of the pedometer) [35, 36], health education and awareness workshops and sessions on diet, physical activity, and obesity risk factors [37, 40, 41, 43, 44], and counselling sessions [38, 39].

Out of the eleven studies, only two [35, 45] used the persuasion function to change participants’ behaviours. There were changes in the perceptions of the intervention group in one study [35], and positive attitudes were reported in the other study [45]. Similarly, incentivisations were reported in two studies [36, 38]. In Allafi’s study [36], the FB + R group was provided with rewards in the form of stickers for achieving the step count milestone. However, in Choudhury’s study [38], participants received stamps in a book when they chose a healthy option in the cafeteria and were awarded a badge at the end, to motivate and reinforce healthy eating behaviours.

Interventions via training were reported in six studies [36, 37, 39, 42, 44, 45], where the participants were engaged in various practical activities related to nutrition, physical activity, and body image perception (see Table 2). Environmental restructuring was reported in three studies in the forms of food labelling and promotion of healthy diets at the school cafeteria [40] and redesigning the school canteen, which included posters and leaflets about healthy diets [38] a