Effectiveness of Gradual Versus Rapid Weight Loss

Study Overview
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Brief Summary
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This randomized controlled trial aims to compare the 1-year effectiveness of an initial rapid weight loss (RWL) program and a gradual weight loss (GWL) program.

Detailed Description
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A total of at least 286 participants will be randomized to either a 16-week rapid weight loss (RWL) program; [an 8-week low-energy-diet (<1000 kcal/day) - followed by an 8-week gradual increase in energy intake (4 weeks <1300 kcal/day and 4 weeks <1500 kcal/day)], or a 16-week gradual weight loss (GWL) program (controls); [estimated total energy expenditure minus 800-1000 kcal/day]. Thereafter, all participants (both groups) will undergo a 36-week comprehensive weight maintenance program.

Official Title
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Comparative Effectiveness of a Gradual Weight Loss Program and a Rapid Weight Loss Program (Including a Low Energy Diet) on 1-year Weight Loss in Subjects With Obesity - A Randomized, Parallel-group, Superiority Trial. (The GoLow Study).

Conditions
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Obesity

Intervention / Treatment
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* Other: Rapid weight loss (RWL) program
* Other: Gradual weight loss (GWL) program


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: • Willing and able to give informed consent for participation in the study Living in the eastern part of Norway, mainly Oslo, Buskerud, Vestfold and Akershus Understanding Norwegian language written and spoken easily BMI ≥30.0 kg/m2 Stable body weight (<5 kg self-reported weight change) during the last 3 months before inclusion Exclusion Criteria: • Pregnancy and breast-feeding mothers Suspected non-compliance with regards to visits and/or diet Severe chronic disease (endocrine disease, heart disease, neurological disease, lung disease, disease in the gastrointestinal tract, kidney disease, rheumatism or cancer).

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Interventional Model Description: Randomized controlled study
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Rapid weight loss (RWL) program<br>16-week rapid weight loss (RWL) program [8-week LED (<1000 kcal/day) - followed by an 8-week gradual increase in energy intake (4 weeks <1300 kcal/day and 4 weeks <1500 kcal/day)] followed by a 36-weight loss maintenance program. | Other: Rapid weight loss (RWL) program<br>* 16-week rapid weight loss (RWL) program (8-week low energy diet (LED) followed by 8-week gradual increased energy intake) and a subsequent 36-week weight-maintenance follow-up<br>|
| Active Comparator: Gradual weight loss (GWL) program<br>16-week GWL-program (estimated total energy expenditure minus 800-1000 kcal/day) followed by a 36-weight loss maintenance program. | Other: Gradual weight loss (GWL) program<br>* 16-week gradual weight loss (GWL) program (moderate calorie restriction) and a subsequent 36-week weight-maintenance follow-up<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in body weight from baseline to 12 months | Percent total body weight loss (%TBWL) at 12 months follow-up | Baseline to 1-year | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Changes in anthropometric measures | Waist and hip circumference (cm) | 4-month and 1-year | 
| Changes in body composition 1 | Bioelectrical Impedance Analysis (BIA) | 4-month and 1-year | 
| Changes in body composition 2 | Dual-energy X-ray Absorptiometry (DXA) in selected participants | 4-month and 1-year | 
| Changes in lipids | Total-cholesterol, HDL-cholesterol, LDL-cholesterol and triglycerides (mmol/l) | 4-month and 1-year | 
| Changes in blood pressure | Systolic and diastolic blood pressure (mm/Hg) | 4-month and 1-year | 
| Changes in glucose parameters | HbA1c (mmol/mol) | 4-month and 1-year | 
| Changes in CRP | CRP (mg/L) | 4-month and 1-year | 
| Changes in Health Related Quality of Life 1 | Generic questionnaire: Short Form-36 Health Survey, SF36. Each item is scored on a 0 to 100 range so that the lowest and highest possible scores are 0 and 100, respectively. Scores for each of the 8 domains and summary scores for physical and mental health will be calculated | 4-month and 1-year | 
| Changes in Health Related Quality of Life 2 | Obesity specific questionnaire: IWQOL-lite. The IWQOL-Lite is a 31-item measure of weight-related quality of life. There are five domain scores (Physical Function, Self-Esteem, Sexual Life, Public Distress and Work) and a total score. Scores for all domains and total score range from 0-100, with lower scores indicating greater impairment. | 4-month and 1-year | 
| Changes in Health Related Quality of Life 3 | Weight-related Symptom Measure (WRSM). The validated obesity specific WRSM measures 20 symptoms commonly related to being overweight or obese, including foot problems, joint pain, sensitivity to cold, shortness of breath, etc. using two different sets of items. The first set assesses whether or not a patient is experiencing specific symptoms, and the second set rates the level of the distress of the symptoms with values from zero (not at all) to six (bothers a very great deal). The first set creates an additive scale summing symptoms from 0-20, while the second forms a symptom distress scale ranging from 0-120. | 4-month and 1-year | 
| Changes in symptoms of depression and anxiety | Hospital Anxiety and Depression Scale (HADS). The validated generic HADS measures symptoms of anxiety and depression using 14 items scored from 0-3 It is decomposed into two domains measuring depression (HADS-D) and anxiety (HADS-A), both consisting of seven items yielding a score from 0-21. | 4-month and 1-year | 
| Changes in eating behavior | The Three Factor Eating Questionnaire -R 21 (TFEQ-R21) measures eating behaviour and has been validated for use in individuals with obesity and will be used in the study. It consists of 21 items comprising three domain scores; (1) uncontrolled eating; assessing the tendency to lose control over eating when feeling hungry or when exposed to external stimuli, (2) cognitive restraint; assessing the conscious restriction of food intake to control body weight or body shape, and (3) emotional eating; assessing overeating related to negative mood states. The domain scores were transformed to 0-100 scales to facilitate comparison; a higher score indicates more uncontrolled, restraint, or emotional eating. | 4-month and 1-year | 
| Change in weight from baseline to 4 months | Percent total body weight loss (%TBWL) at 4 months follow-up | 4-month | 
| Proportions of participants with a TBWL of ≥ 5%, ≥10% and ≥15% at 52-week | TBWL of ≥ 5%, ≥10% and ≥15% at 52-week follow-up | 1-year |