A randomized parallel-designed study evaluating the effect of an app-based nutritional concept for weight reduction and further cardiovascular risk factors: Insights from the PreVA study.

INTRODUCTION: Overweight is a major public health concern. Beyond traditional dietary therapy, mobile health (mHealth) applications have gained interest for their potential to support weight loss. However, evidence on their efficacy remains limited. This study evaluated the effectiveness of an app-based dietary concept for weight reduction and improvement of further cardiovascular risk factors. Methods: The PreVa study is a single-center, randomized, four-arm parallel intervention study comparing an app-based nutrition program with standard therapy involving personal counseling. Eighty adults with a body mass index between 25 and < 35 kg/m2 were randomly assigned to one of four groups (1) app-based, (2) individual coaching, (3) general dietary recommendations and (4) control. All intervention groups received individualized, nutrient-optimized menu plans with integrated flaxseed oil supplementation, either via app or in printed form, combined with varying levels of counseling. Energy intake was gradually reduced every 4 weeks, with maintenance phases at the beginning and end of the 16-week intervention. Anthropometric and biochemical parameters were measured at four-week intervals.

RESULTS: After 12 weeks of energy reduction, weight loss was significantly greater in the intervention groups (-6.5 %, -7.3 %, -6.0 %) than in the control group (-2.1 %; p < 0.001) and remained stable during the maintenance phase (16 weeks; all p < 0.01). A clinically relevant (> 5 %) weight loss was achieved by 66.7 %, 78.9 %, and 53.3 % of participants for all interventions, respectively. Blood pressure was reduced in all intervention groups (p < 0.05), while the values differ not significantly from control group. Total and LDL cholesterol decreased in group 2 and 3 (p < 0.05), the changes differ significantly from the control group. Group 1 exhibited a significant decrease in fasting glucose and HOMA-IR compared to the other groups. α-Linolenic concentrations increased markedly (+ 52.7-79.4 %; p ≤ 0.01), whereas eicosapentaenoic acid and docosahexaenoic acid remained unchanged. No relevant changes were observed in micronutrient status.

CONCLUSION: The intervention groups achieved clinically meaningful weight loss and an improvement in blood lipid levels. The greatest effect is likely attributable to the individualized, nutrient-optimized menu plans rather than the type of counseling or delivery mode.

CLINICAL TRIAL REGISTRATION: https://clinicaltrials.gov/, identifier NCT04717076.