The “More Health, Less Diabetes” Randomized Controlled Trial: A Digital and In-Person Educational and Exercise Program for Type 2 Diabetes Prevention Study Protocol

Background Type 2 diabetes mellitus (T2DM) is a major global health issue, with prevalence and healthcare-related costs rising every year. Lifestyle-related factors such as physical inactivity and unhealthy diets play a central role in disease progression. Exercise has consistently been shown to improve glycemic control at the individual level and, in large-scale prevention trials, to reduce the incidence of T2DM among high-risk populations; however, heterogeneity in intervention design and delivery limits comparability across studies. Online interventions are scalable and inexpensive, but may have limited effectiveness in sustaining health outcomes over time.. Our aim is to assess the effectiveness and cost-effectiveness of a 6-month in-person versus online lifestyle intervention in individuals at high risk of developing T2DM within 10 years. Methods A randomized controlled trial (RCT) will be conducted to evaluate the effectiveness and cost-effectiveness of a 6-month lifestyle intervention delivered in-person or online. For this RCT, adults at high risk of developing T2DM, as determined by the FINDRISC score, will be recruited from Portuguese primary health care units. Participants will be randomly assigned to one of three groups: an in-person intervention group (IPIG), an online intervention group (OIG), or a control group. The IPIG will participate in a 6-month program consisting of three exercise sessions per week and seven educational sessions throughout the 6-month intervention. At the same time, the OIG will follow the same online program. The control group will attend a single orientation session. During the subsequent 6-month follow-up, all participants will have the option to attend in-person exercise sessions. The primary outcome will be postprandial glucose, assessed by blood analysis following a 2-hour 75g oral glucose tolerance test. The secondary outcomes will include variables related to body composition, cardiorespiratory fitness, handgrip strength, 24-h movement accelerometry, diet, and cost-effectiveness. Primary and secondary outcomes will be measured at baseline, 6 months of intervention, and 12 months of follow-up. Discussion Lifestyle programs are effective and cost-effective for people at risk of T2DM, but the optimal intervention type, design, and delivery remain unclear. This trial will serve as a proof-of-concept, implementing an evidence-based lifestyle intervention program tailored to individuals at risk of T2DM and evaluating the comparative effectiveness and cost-effectiveness of in-person versus online lifestyle interventions. The findings will inform future large-scale strategies for T2DM prevention. Trial registration: This study was retrospectively registered (NCT07079722), and the details are at: https://clinicaltrials.gov/study/NCT07079722 Registered on July 23, 2025**.