Effects of a web-based lifestyle intervention in adults with overweight and obesity on weight loss and cardiometabolic risk factors: a randomized controlled clinical trial (Preprint)

BACKGROUND The high proportion of people with overweight and obesity has become a worldwide problem in recent decades, mainly due to the health consequences such as cardiovascular diseases, neoplasia, or type 2 diabetes mellitus. Regarding effective countermeasures, the digitization of health services offers numerous potentials, which, however, have not yet been sufficiently evaluated. Web-based health programs are becoming increasingly interactive and can provide individuals with effective long-term weight management support. OBJECTIVE The purpose of this randomized controlled clinical trial was to evaluate the effectiveness of an interactive web-based weight loss program on anthropometric, cardiometabolic, and behavioral variables and to compare it with a non-interactive web-based weight loss program. METHODS The randomized controlled trial included people between 18 and 65 years of age (mean 48.92, SD 11.17) with a body mass index (BMI) of 27.5 to 34.9 kg/m2 (mean 30.71, SD 2.13). Subjects (n=153) were assigned to either i) an interactive and fully automated web-based health program (intervention) or ii) a non-interactive web-based health program (control). The program of the intervention focused on dietary energy density and allowed for documentation of diet with appropriate feedback on energy density as well as nutrients. In addition, other goals to improve diet or increase physical activity and informational texts could accompany the program. The control group only received information on weight loss and energy density, but the website did not contain interactive content. Examinations were performed at baseline (t0), at the end of the 12-week intervention (t1), 6 months (t2) and 12 months (t3) thereafter. Body weight was defined as the primary outcome. Secondary outcomes were cardiometabolic variables (blood lipids, blood pressure and blood glucose) and dietary (energy density, energy intake and macronutrients) and physical activity behaviors (total physical activity). Robust linear mixed models were used to evaluate the primary and secondary outcomes. RESULTS The intervention group improved significantly over the control group in anthropometric variables such as body weight (P=.004), waist circumference (P=.002), and fat mass (P=.019) over the course of the study. Compared to the initial weight, the mean weight loss after 12-month follow-up was 4.18 kg (4.7%) in the intervention group versus to 1.29 kg (1.5%) in the control group. The results of the nutritional analysis showed that the energy density concept was significantly better implemented in the intervention group. Significant differences in cardiometabolic variables were not detected between both groups. CONCLUSIONS The interactive web-based health program was effective in reducing body weight and improving body composition in adults with overweight and obesity. However, these improvements were not associated with relevant changes in cardiometabolic variables, although it should be noted that the study population was predominantly metabolically healthy. CLINICALTRIAL World Health Organization approved German Clinical Trials Register (DRKS00020249, https://www.drks.de) INTERNATIONAL REGISTERED REPORT RR2-10.3390/ijerph19031393