Weight Loss Maintenance and Compensatory Mechanisms Activated With a Very-low Calorie Diet

Study Overview
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Brief Summary
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Very-low calorie diets are relatively safe and effective in inducing significant weight loss, when used in selective individuals and under clinical supervision. However, weight loss maintenance in the long-term remains the main challenge, with many experiencing a significant weight regain. Several compensatory mechanisms are activated under weight reduction, both at the level of energy intake (such as increased appetite) and energy expenditure (such as reduced energy expenditure), and increase the risk of relapse. The main aim of this study is to compare the effect of two multidisciplinary lifestyle interventions on weight loss maintenance at one year, after initial weight loss during 8 weeks very-low calorie diet. Participants will be allocated (non-randomly) to either an outpatient program in the obesity unit of the local hospital, or to an inpatient program consisting of a continuous care intervention, with three intermittent stays (each with three-week duration) in a rehabilitation center over a one year period. Moreover, the investigators aim to assess the impact of weight loss (achieved with a very low calorie diet) and weight loss maintenance on compensatory mechanisms activated during weight reduction.

Detailed Description
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This study included a sub-study (n=30) to determine the timeline over which compensatory mechanisms (at both the level of energy expenditure and appetite control system) are activated with progressive weight loss. Additional measurements were taken at day-3, 5 and 10 % weight loss, and after 4 weeks weight stabilization (after gradually reintroduction of food).

Official Title
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How to Optimize Weight Loss Maintenance After a Very-low Calorie Diet?

Conditions
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Obesity, Morbid

Intervention / Treatment
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* Behavioral: Multidisciplinary outpatient program
* Behavioral: Inpatient lifestyle program


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: volunteers from Central Norway if female: taking oral contraceptives or post-menopausal body mass index 30-45 kg/m2 stable weight (<2kg variation in the last 3 months) not currently dieting to lose weight Exclusion Criteria: Pregnancy breast feeding drug or alcohol abuse within the last two years current medication known to affect appetite or induce weight loss enrollment in another obesity treatment program history of psychological disorders history of eating disorders history of diabetes type 1 or 2 gastrointestinal disorders (particular cholelithiasis) kidney -, liver -, lung- or cardiovascular disease malignancies

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 65 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Non-Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Outpatient<br>Multidisciplinary outpatient program including both individual and group-based therapy. During the first visit, there will be offered an individual consultation with the dietician, physiotherapist and psychiatric nurse. Follow-up will be in groups meeting every month for the first four months and every two months afterwards up to one year. The intervention will focus on nutritional education, healthy eating, increased physical activity levels (aiming initially at 10 minutes/day, then increasing to 30 minutes/day) and cognitive therapy. | Behavioral: Multidisciplinary outpatient program<br>* Diet (phase 1) and multidisciplinary lifestyle intervention (phase 2)<br>|
| Experimental: Inpatient<br>Inpatient lifestyle program consisting of a continuous care weight loss program offered at a rehabilitation center, with three intermittent stays (each with 3-week duration) over a one year period. | Behavioral: Inpatient lifestyle program<br>* Diet (phase 1) and lifestyle intervention (phase 2)<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| body weight | body weight change after end of very-low calory diet | 1 year (changes from baseline to one year) | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| resting metabolic rate, short-term | using indirect calorimetry | 10 weeks | 
| appetite, short-term | assessed through: the Three-Factor Eating Questionnaire (TFEQ) fasting and postprandial release of appetite related hormones in blood samples, for a period of 3h (0, 30, 60, 120, 180 minutes), after a standard breakfast feelings of hunger/fullness by a visual analog scale | 10 weeks | 
| exercise efficiency, short-term | assessed through graded cycle ergometry and indirect calorimetry | 10 weeks | 
| physical activity level, short-term | measurement with arm bands | 10 weeks | 
| resting metabolic rate, long-term | using indirect calorimetry | 1 year | 
| appetite, long-term | assessed through: the Three-Factor Eating Questionnaire (TFEQ) fasting and postprandial release of appetite related hormones in blood samples, for a period of 3h (0, 30, 60, 120, 180 minutes), after a standard breakfast feelings of hunger/fullness by a visual analog scale | 1 year | 
| exercise efficiency, long-term | assessed through graded cycle ergometry and indirect calorimetry | 1 year | 
| physical activity level, long-term | measurement with arm bands | 1 year | 
| Sleep duration and quality | Sleep duration and quality will be measured using The Pittsburgh Sleep Quality Index (PSQI) | Baseline, end of weigth loss phase and 1 year | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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weight reduction programs, diet, Caloric restriction, weight loss, weight gain