Background: As formula diets have demonstrated to be effective in reducing weight, we hypothesised that in patients with overweight or obesity and accompanied cardiovascular risk factors, combining a liquid formula diet with a lifestyle intervention is superior in reducing weight and improving cardiovascular risk factors than lifestyle intervention alone.
Methods: In this multicenter RCT 463 participants with overweight or obesity (BMI: 27-35 kg/m²; at least one additional co-morbidity of the metabolic syndrome) were randomised (1:2) into either a control group with lifestyle intervention only (CON, n = 155) or a lifestyle intervention group including a liquid meal replacement (INT, n = 308). Both groups used telemonitoring devices (scales and pedometers), received information on healthy diet and were instructed to increase physical activity. Telemonitoring devices automatically transferred data into a personalised online portal and acquired data were discussed. INT obtained a liquid meal replacement substituting three meals/day (~1200 kcal) within the first week. During weeks 2-4, participants replaced two meals/day and during weeks 5-26 only one meal/day was substituted (1300-1500 kcal/day). Follow-up was conducted after 52 weeks. Intention-to-treat analyses were performed. Primary outcome was weight change. Secondary outcomes comprised changes in cardiometabolic risk factors including body composition and laboratory parameters.
Results: From the starting cohort 360 (78%, INT: n = 244; CON: n = 116) and 317 (68%, INT: n = 216; CON: n = 101) participants completed the 26-weeks intervention phase and the 52-weeks follow-up. The estimated treatment difference (ETD) between both groups was -3.2 kg [-4.0; -2.5] (P < 0.001) after 12 weeks and -1.8 kg [-2.8; -0.8] (P < 0.001) after 52 weeks.
Conclusions: A low-intensity lifestyle intervention combined with a liquid meal replacement is superior regarding weight reduction and improvement of cardiovascular risk factors than lifestyle intervention alone.