Digital dietary interventions for healthy adolescents: A systematic review of behavior change techniques, engagement strategies, and adherence.

Background: Adolescence is a crucial phase for developing healthy eating habits with lifelong health implications. Digital interventions, such as smartphone apps and web platforms, have emerged as promising strategies to promote healthy eating habits among adolescents by using behavior change techniques (BCTs). This study aims to systematically review internet-based dietary interventions targeting adolescents, focusing on the analysis of BCTs employed, their delivery modes, and their impact on adolescents' adherence and engagement.

Methods: PubMed, Scopus, and Web of Science databases were used up to July 2024. Eligible studies included randomized clinical trials involving adolescents aged 12 to 18. The interventions analyzed involved smartphone apps and web platforms promoting changes in eating habits, with results focusing on adherence and techniques used.

Results: The initial search identified 5399 articles, of which 16 studies were included in the final analysis. The studies involved a total of 31,971 participants (range: 29-7890), with 40.29 % being female (n = 12,881), aged 12-18 years. The duration of interventions ranged from two weeks up to 12 months, with follow-ups of up to 24 months. Interventions that utilized BCTs such as goal setting (n = 14), feedback on behavior (n = 14), social support (n = 14), prompts/cues (n = 13), and self-monitoring (n = 12), were the most effective in promoting adherence and engagement. Digital dietary interventions that incorporated personalized feedback (n = 9) and gamification (n = 1) showed adherence rates between 63 % and 85.5 %, with notable improvements in dietary habits, such as increased fruit and vegetable consumption and reduced intake of sugar-sweetened beverages. However, the intervention using gamification involved only 36 participants, and its effects require further investigation due to the limited sample size.

Conclusion: Digital interventions show potential for promoting healthy dietary behaviors among adolescents, yet mixed outcomes underscore the challenges of maintaining adherence and long-term engagement. Techniques such as self-monitoring, goal setting, and social support can enhance engagement and effectiveness, particularly when combined with gamified features. The trial protocol is registered on PROSPERO (CRD42024564261).