Overweight and obesity are becoming increasingly prevalent among children and adolescents in Saudi Arabia and are an emerging cause of non-communicable diseases (NCDs). Lifestyle factors, such as insufficient levels of physical activity and sedentary behaviors, are responsible for the increased prevalence of NCDs. This study aimed to determine the association between physical activity levels, sedentary behaviors, and anthropometric measurements in Saudi female adolescents. A cross-sectional study was carried out among 399 healthy female adolescent students aged 13–14 years in Arar, Saudi Arabia. The participants were randomly selected from different schools and their anthropometric measurements were determined. The Physical Activity Questionnaire for Older Children (PAQ-C) and the Adolescent Sedentary Activity Questionnaire (ASAQ) were used to assess their physical activity levels and sedentary behaviors, and an analysis was conducted using IBM SPSS software version 25. A multiple linear regression model was used to determine the association between the variables. The majority of the participants had a normal body mass index (BMI; 79.4%) and waist circumference (WC; 62.4%). A total of 74.4% had waist to height ratio (WHtR) < 0.5. About 92.7% of the participants were not meeting PA recommendations of 60 min of moderate to vigorous physical activity daily. The overall mean time spent on sedentary activities was high on both weekdays and weekend days at 357.64 ± 86.29 and 470.51 ± 147.64 min/day, respectively. Moreover, anthropometric measurement (BMI) was positively associated with age and negatively associated with sedentary behavior on weekends, while WHtR was positively associated with age. The multiple linear regression analysis also showed that age and sedentary behavior significantly predicted BMI among the study participants (F (2, 396) = 4.346, p < 0.014) and age was the only significant predictor of WHtR (F (1, 397) = 16.191, p ≤ 0.001). This study revealed that most of the female Saudi adolescents undertook low levels of activity and high levels of sedentary behaviors. Sedentary behaviors were significantly associated with their BMI. Accordingly, an intervention program on healthy lifestyles is important to improve Saudi female adolescents’ lifestyles.

Background: This cluster-randomized study aimed to evaluate the effects of an intervention focused on physical activity, nutrition, and body image perception among girls in intermediate schools in Saudi Arabia. A seminar was delivered to the mothers of the girls in the experimental group. The experimental group then attended six interactive sessions within 3 months featuring physical activity, nutrition, and body image perception, followed by a 3-month follow-up period. A total of 138 respondents (68 in the experimental group and 70 in the control group) completed the intervention. Each participant’s body mass index-for-age z-score and waist circumference were measured, and they completed a physical activity, sedentary behavior, and body image perception questionnaires before and after the intervention and at the follow-up. The intervention was evaluated using within- and between-groups generalized estimating equations. There were no significant changes in the respondents’ body mass index-for-age z-score or waist circumference (p > 0.05). However, immediate significant improvements were seen in physical activity, sedentary behavior, and body image satisfaction among the experimental group, and these improvements remained at follow-up (p < 0.001). These differences were more significant among the experimental group than among the control group. We found this intervention effective. Future studies can adapt this intervention for adolescent boys and extend its duration to improve the body mass index outcome.

Unhealthy food intake, physical inactivity, and body image (BI) dissatisfaction could potentially lead to obesity and health problems. This cluster-randomized intervention study aimed to investigate the effectiveness of a nutrition and physical activity (PA) intervention on related knowledge, attitudes, and practices among Saudi adolescent girls (aged 13–14) living in Arar City. One hundred thirty-eight girls were selected and recruited randomly from two schools. The respondents in the intervention group (IG; n=68) received a three-month intervention program that consisted of six 90- minute sessions. The participants in the control group (CG; n=70) received only their traditional education and did not receive the intervention program. The groups’ total pre-test scores for practices were significantly different; therefore, the pre-test scores were used as covariates. The IG demonstrated significant improvements in knowledge, attitudes, and practices (p<0.001 for all), and improvement in the IG was greater than that in the CG at the post- test and three-month follow-up time points (p<0.001 for both). These findings provide evidence of the significant influence of a nutrition, PA, and positive BI intervention on related knowledge, attitudes, and practices among Saudi adolescent girls.

Aims: This study aimed to examine the influence of nutrition knowledge on the pathways of the Theory of Planned Behavior (TPB) — specifically attitudes, subjective norms, perceived behavioral control (PBC), intention, and behavior — in predicting ultra-processed food (UPF) consumption among university students is Saudi Arabia. Methods: A cross-sectional design was employed, involving 384 students enrolled at Northern Border University (NBU). Data were collected through a validated questionnaire that assessed socio-demographic characteristics, UPF-related knowledge, TPB factors, and self-reported UPF consumption. Participants were stratified into low, moderate, and high knowledge groups for comparative analysis. Results: Significant associations were observed between UPF knowledge and sex, marital status, and academic discipline. Higher knowledge levels were correlated with less favorable attitudes toward the safety of UPFs and heightened susceptibility to social influence. Structural Equation Modelling (SEM) revealed that, across the overall sample, attitudes significantly predicted behavioral intention (β = 0.59, p < 0.001), whereas perceived behavioral control (PBC) exerted a negative effect on behavior (β = –0.22, p < 0.001). Notably, among participants with high-knowledge, neither intention (p = 0.884) nor PBC (p = 0.453) significantly predicted UPF consumption, and the model accounted for a negligible proportion of variance in behavior (R² = 0.01), indicating a pronounced intention–behavior discrepancy within this group. Conclusions: Among NBU students, nutrition knowledge regulates psychosocial determinants of UPF consumption but appears to weaken the intention–behavior connection. These findings suggest that effective interventions should extend beyond educational initiatives to incorporate habit-formation strategies and environmental modifications that support sustained dietary behavioral modification. Keywords: Ultra-Processed Foods; Theory of Planned Behavior; Nutrition Knowledge; Saudi Arabia; University Students.