Background: Childhood and adolescent obesity is a growing global health issue linked to noncommunicable diseases such as cardiovascular disease and type 2 diabetes. Digital health technologies, including mobile apps and web-based programs, offer scalable tools to improve health behaviors, but their effectiveness in young populations remains unclear. Objective: This systematic review aimed to evaluate the effectiveness of mobile and web-based digital interventions in promoting healthy diets, reducing obesity risk, increasing physical activity, and improving nutrition-related knowledge and attitudes among children and adolescents. Methods: A systematic search was conducted across PubMed, Scopus, Web of Science, and Google Scholar databases, along with hand-searching reference lists of key systematic reviews. The search encompassed records published up to September 30, 2024. Eligible studies were randomized controlled trials targeting dietary intake, anthropometric measurements, physical activity, or nutrition-related attitudes and knowledge among participants aged ≤18 years. Screening, full-text eligibility assessment, and data extraction were done partly in duplicate (20%; κ=0.86 for title or abstract screening, κ=0.71 for full-text eligibility assessment, and κ=0.78 data extraction). Risk of bias was evaluated using the Cochrane Risk-of-Bias tool (κ=0.71 for interrater reliability of 20% duplicate evaluation). Data were synthesized narratively. Results: From 300 records screened, a total of 37 articles (34 studies) were included. Interventions included games, (in 21/34 studies, 62%), mobile apps, web-based programs, and other digital tools. Among the 34 included studies, 23 (68%) studies reported positive outcomes for at least 1 measured variable. Fruit intake improved in 17 of 34 studies (50%) assessing fruit intake, while 7 of 34 studies (21%) targeting sugar-sweetened beverage consumption showed reductions. Improvements in nutrition knowledge were reported in 23 of 34 (68%) studies, but changes in anthropometric measures and physical activity outcomes showed no effect. Risk of bias was low for random sequence generation but high or unclear in other domains for many studies. Conclusions: Mobile- and web-based interventions, particularly game-based tools, show promise for promoting healthy dietary behaviors and increasing nutrition knowledge in children and adolescents. However, the evidence for long-term sustainability and impact on anthropometric and physical activity outcomes remains limited. Future research should focus on understanding which digital features drive effectiveness, extending follow-up periods, and exploring the role of family involvement in interventions. Trial Registration: PROSPERO CRD42023423512; https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=423512

Background: Growing concerns about health and sustainability are accelerating the need to transform food systems to promote well-being and reduce environmental impacts. Despite increasing policy efforts, evidence remains limited on self-perceived knowledge, reported practices, intentions, and perceived barriers related to healthy and sustainable eating among European households with children. Establishing healthy eating habits during childhood is essential for long-term health, with parents playing a pivotal role in shaping these behaviors. Understanding the factors and barriers related to food choices is essential for informing interventions that support healthier and more sustainable dietary practices. Methods: This study, conducted in 2023 as part of the European TITAN project, explored parental perceptions and practices related to healthy and sustainable eating in Spain, Poland, and Finland. A structured questionnaire was completed by 240 parents of children aged 6–12 in each country using quota sampling based on national income tertiles. Results: Although households reported high self-perceived knowledge, patterns consistent with a possible discrepancy between self-perceived knowledge and reported food choices were observed. Finnish households, despite showing the highest recognition of predefined healthy and sustainable eating concepts, reported lower self-reported adherence to healthy and sustainable practices. Reducing meat consumption and choosing sustainably sourced seafood were among the least valued actions across all countries. Cost was the most frequently reported barrier, especially in Finland (60%), alongside greater difficulty in forming new habits and resisting less healthy options. Overall, cost and behavioral constraints were among the most frequently reported barriers to healthier and more sustainable dietary practices. Conclusions: These findings highlight the need for culturally tailored strategies to support households in transitioning toward healthier and more sustainable dietary behaviors. Addressing perceived barriers and food-choice constraints may be important for supporting healthier and more sustainable dietary practices at the household level.

BACKGROUND Childhood and adolescent obesity is a growing global health issue linked to noncommunicable diseases such as cardiovascular disease and type 2 diabetes. Digital health technologies, including mobile apps and web-based programs, offer scalable tools to improve health behaviors, but their effectiveness in young populations remains unclear. OBJECTIVE This systematic review aimed to evaluate the effectiveness of mobile and web-based digital interventions in promoting healthy diets, reducing obesity risk, increasing physical activity, and improving nutrition-related knowledge and attitudes among children and adolescents. METHODS A systematic search was conducted across PubMed, Scopus, Web of Science, and Google Scholar databases, along with hand-searching reference lists of key systematic reviews. The search encompassed records published up to September 30, 2024. Eligible studies were randomized controlled trials targeting dietary intake, anthropometric measurements, physical activity, or nutrition-related attitudes and knowledge among participants aged ≤18 years. Screening, full-text eligibility assessment, and data extraction were done partly in duplicate (20%; κ=0.86 for title or abstract screening, κ=0.71 for full-text eligibility assessment, and κ=0.78 data extraction). Risk of bias was evaluated using the Cochrane Risk-of-Bias tool (κ=0.71 for interrater reliability of 20% duplicate evaluation). Data were synthesized narratively. RESULTS From 300 records screened, a total of 37 articles (34 studies) were included. Interventions included games, (in 21/34 studies, 62%), mobile apps, web-based programs, and other digital tools. Among the 34 included studies, 23 (68%) studies reported positive outcomes for at least 1 measured variable. Fruit intake improved in 17 of 34 studies (50%) assessing fruit intake, while 7 of 34 studies (21%) targeting sugar-sweetened beverage consumption showed reductions. Improvements in nutrition knowledge were reported in 23 of 34 (68%) studies, but changes in anthropometric measures and physical activity outcomes showed no effect. Risk of bias was low for random sequence generation but high or unclear in other domains for many studies. CONCLUSIONS Mobile- and web-based interventions, particularly game-based tools, show promise for promoting healthy dietary behaviors and increasing nutrition knowledge in children and adolescents. However, the evidence for long-term sustainability and impact on anthropometric and physical activity outcomes remains limited. Future research should focus on understanding which digital features drive effectiveness, extending follow-up periods, and exploring the role of family involvement in interventions. CLINICALTRIAL PROSPERO CRD42023423512; https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=423512