Impact of social media-driven dietary trends on obesity and BMI in Saudi Arabia: an online cross-sectional study

Social media platforms, such as Instagram and Snapchat, shape dietary behaviors and obesity in Saudi Arabia, where cultural and lifestyle factors contribute to high obesity rates. This study investigates the impact of social media-driven dietary trends (e.g., ketogenic diets, weight-loss challenges) on Body Mass Index (BMI) among Saudi nationals aged 15–35, exploring demographic (age, gender, marital status) and behavioral (dietary habits, fast-food consumption) mediators of this relationship. A cross-sectional online survey sampled 386 participants using non-probability convenience sampling via WhatsApp, Instagram, and Twitter. Linear regression and Pearson correlation analyses assessed social media exposure (food pages, influencers), dietary behaviors, and demographics as predictors of BMI, controlling for dietary habits. Social media exposure was measured using a composite score (1–5) from survey questions on food-related content and influencer engagement. Data were collected via an Arabic questionnaire distributed on WhatsApp, Instagram, and Twitter. Social media exposure showed weak BMI correlations (food pages, r = 0.024; influencers, r = 0.010), but 62.4% adopted dietary trends (weight-loss challenges, 19.9%; ketogenic diets, 18.9%), with higher adoption among obese/overweight (67.2%) than normal/underweight (57.3%) individuals. Linear regression identified marital status (B = 3.541, p < 0.001), gender (B = − 1.856, p = 0.007), and age (B = − 0.050, p = 0.006) as significant BMI predictors, with married individuals and males at higher risk, and older age linked to lower BMI. Fast-food consumption (65% “often” or “always”), influenced by social media, mediated obesity risk indirectly. Pearson correlations confirmed associations for marital status (r = 0.376, p < 0.01), gender (r = − 0.252, p < 0.01), and age (r = − 0.324, p < 0.01); education (r = 0.069, p > 0.05) and income (r = − 0.037, p > 0.05) were non-significant. Regional differences were excluded to focus on national trends. Social media-driven dietary trends indirectly influence obesity via demographic (gender, marital status, age) and behavioral (fast-food consumption) mediators, supported by regression analysis (R2 = 0.163, p < 0.001). Culturally tailored interventions, leveraging influencer collaborations and nutrition education, are crucial to mitigate obesity in Saudi Arabia’s socio-cultural context.