Randomized Controlled Lifestyle Intervention (LION) Study for Weight Loss and Maintenance in Adults With Obesity-Design and Methods

Abstract

Introduction: Due to the increasing prevalence of obesity, approaches for a more effective treatment especially in the long-term perspective are needed. However, studies on weight loss and maintenance show heterogeneous results with large inter-individual variations. Therefore, it is of interest to identify factors that contribute to inter-individual differences and predict the success of long-term weight management. Methods and Analysis: The primary outcome of the Lifestyle Intervention (LION) Study is to evaluate the effect of two diets (low carb vs. low fat) and two digital counseling tools (newsletter vs. mobile application) on weight maintenance 12 months after weight loss. The identification of predictive factors (e.g., genetic, epigenetic, physiological, psychological) for the success of weight loss and maintenance is a secondary outcome. Men and women with a body mass index (BMI) between 30.0 and 39.9 kg/m², aged 18-65 years, and without severe diseases are considered eligible. After phenotyping (e.g., anthropometry, resting metabolic rate, meal challenges, blood parameters) participants will follow a formula-based, low-calorie diet (LCD) for 8 weeks. In addition, the intake of 200 g raw or cooked non-starchy vegetables are allowed per day. Subsequently, 252 participants will be randomized into one of the four intervention groups (low carb/app, low carb/newsletter, low fat/app, low fat/newsletter) for the 12-month weight maintenance step. The study will be concluded after another 12 months of follow-up. Results should provide indications for successful weight management and give insights into the personalized treatment of obesity. Ethics and Dissemination: This study has been granted ethical approval by the local Ethics Review Committee of the School of Medicine, Technical University of Munich (vote: 69/19 S). Trial Registration Number: This study has been registered within ClinicalTrials.gov (NCT04023942) and the German Clinical Trials Register (DRKS00017819).

Keywords: formula diet; lifestyle; low carb; low fat; mobile application (app); obesity; personalized nutrition; weight maintenance.

Figure 1

Study design. Numbers indicate measurements performed during the corresponding visit. (1) Screening questionnaire, (2) anthropometry, (3) collection of biomaterial, (4) meal challenge, (5) questionnaires/protocols, (6) vital parameters, (7) resting metabolic rate, (8) magnetic resonance imaging (subgroup), (9) physical functional performance test (subgroup), (10) hand strength measurement, (11) continuous glucose measurement. * Randomization of the test meal and selected measures. The exact time point of measurements marked by a bracket is dependent of randomization.

Figure 2

(A) First randomization: meal challenges. After the telephone-based screening and before the first visit, the order of meal challenges as well as the type of lipid meal challenge will be randomized. Two meal challenges are carried out per participant (one during Visit V1A and one during Visit V1B). Oral glucose tolerance test (OGTT), oral glucose and lipid mixed meal challenge (OG+LTT), oral lipid tolerance test (OLTT). (B) Second randomization: weight maintenance intervention. After weight loss (during the Visit V2), participants are randomized to one of the four intervention groups. The second randomization is stratified according to the parameters of the first randomization. No results of the meal challenge tests (blood and other metabolic parameters) are considered for randomization.