The Effectiveness of Multiple Interventions in Promoting Healthy Lifestyle Behaviors among Adults at Risk for Disease: A Systematic Review of Randomized Controlled Trials

Lifestyle choices play a critical role in maintaining health and preventing chronic diseases.This systematic literature review, guided by the PICOS framework, aimed to evaluate the effectiveness of educational, behavioral, digital, and community-based interventions in promoting healthy behaviors and reducing obesity among adults (18 years).A comprehensive search was conducted in PubMed, Scopus, Web of Science, and Google Scholar to identify eligible randomized controlled trials (RCTs) and cluster-RCTs using predefined keywords.Of 2004 records retrieved, 25 studies met the eligibility criteria after independent dual screening, with intervention durations ranging from six weeks to eighteen months.The findings indicate that theory-based interventions grounded in models such as the Social Cognitive Theory, the Health Belief Model, and the Theory of Planned Behavior enhanced self-efficacy, improved health beliefs, and supported dietary and physical activity changes, with moderate effects on weight and metabolic markers.Multicomponent lifestyle programsthat integrated education, behavioural counselling, social support, and digital reminders demonstrated greater effectiveness than single-component approaches, producing clinically meaningful reductions in weight, BMI, and waist circumference over 10-12 weeks.Digital and app-based interventions achieved moderate weight loss with partial maintenance up to one year, while long-term lifestyle programs (12 months) yielded sustained improvements in visceral adiposity and postpartum weight retention.In contrast, very short programs (6 weeks) primarily improved psychosocial outcomes and dietary behaviours, with limited impact on anthropometric measures.Heterogeneity in study design,