Optimal Timing of Exercise Initiation Within a Lifestyle Weight Loss Program

Study Overview
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Brief Summary
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The primary aim of this study is to evaluate the extent to which an exercise intervention timed after diet-induced weight loss (rather than initiated at the same time) improves exercise adherence and long-term weight loss. An 18 month randomized trial will be used to compare two behavioral weight loss programs; standard behavioral therapy (Standard BT) and sequential behavioral therapy (Sequential BT). The Standard BT group will receive a traditional behavioral weight loss program where diet and exercise changes are initiated at the same time. The Sequential BT group will receive a program that focuses solely on dietary changes in the initial 6 months, and then incorporates exercise in the ensuing 6 months. Both groups will be followed for 18 months to assess long-term weight loss. The hypothesis is that delivery of diet and exercise interventions in sequence will result in improved adherence to exercise and weight loss at 18 months when compared to a traditional program in which identical diet and exercise interventions are initiated at the same time. This study could identify a strategy that could aid in the development of more effective obesity treatment programs and help more people achieve and sustain a weight loss.

Official Title
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Optimal Timing of Exercise Initiation Within a Lifestyle Weight Loss Program

Conditions
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Obesity

Intervention / Treatment
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* Behavioral: Sequential BT
* Behavioral: Standard BT


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Age 18-55 Body Mass Index 27-42 kilograms/meters squared Sedentary: defined as regular exercise of less than 100 minutes per week at moderate intensity or greater during the previous 6 months No self-report of acute or chronic disease (heart disease, diabetes, gastrointestinal disorders and orthopedic problems in particular) No plans to relocate or for extended travel (more than 1 week) within the next 18 months No current tobacco use Capable and willing to give informed consent, understand exclusion criteria, and accept the randomized group assignment Live or work within 20 minutes of the University of Colorado Anschutz Health and Wellness Center to ensure reasonable ability to comply with requirement to attend group weight loss sessions and supervised exercise sessions. Exceptions can be made at the discretion of the Study Principal Investigator (PI) on a case by case basis for highly motivated subjects. For Females Not currently pregnant or lactating Not pregnant within the past 6 months Not planning to become pregnant in the next 18 months Sexually active women of childbearing potential may be enrolled if they have had a tubal ligation or use a reliable means of contraception. Exclusion Criteria: Presence or history of health problems which would affect appetite, food intake, energy metabolism, or ability to optimally participate in the exercise component including: diabetes, cardiovascular disease, peripheral vascular disease, cerebrovascular disease, uncontrolled hypertension, uncontrolled hyper or hypothyroidism, cancer (within the last 5 years, except skin cancer), human immunodeficiency virus (HIV) infection, significant gastrointestinal, pulmonary, renal, musculoskeletal, neurologic, or hematologic disease Symptoms suggestive of cardiovascular disease: chest pain, shortness of breath at rest or with mild exertion, syncope Abnormal resting electrocardiogram (ECG): serious arrhythmias, including multifocal Premature Ventricular Contractions (PVCs), frequent PVC's (defined as 10 or more per minute), ventricular tachycardia (defined as runs of 3 or more successive PVC's), or sustained atrial tachyarrhythmia; 2nd or 3rd degree A-V block, corrected QT interval > 480 millisecond or other significant conduction defects Triglycerides > 400 milligram/deciliter (md/dL) or Low-Density Lipoprotein (LDL) cholesterol > 190 mg/dL Use of prescription or over-the-counter medications known to affect appetite, weight, heart rate response to exercise, or energy metabolism Use of systemic steroids (other than Oral Contraceptive Pills) Use of obesity pharmacotherapeutic agents within the last 6 months History of surgical procedure for weight loss History of major surgery within the past 3 months Current alcohol or substance abuse History of clinically diagnosed eating disorders including anorexia nervosa or bulimia Current severe depression or history of severe depression within the previous year History of other significant psychiatric illness (e.g. psychosis, schizophrenia, mania, bipolar disorder) which in the opinion of the Study MD would interfere with ability to adhere to dietary or exercise interventions Currently participating in or planning to participate in any formal weight loss or physical activity programs or clinical trials Weight loss or gain of > 5% in past 6 months for any reason except post-partum weight loss Participation in a weight loss program using the Colorado Weigh curriculum within the past 3 years (exceptions can be made at the discretion of the study PI on a case-by-case basis).

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 55 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
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Standard Behavioral Therapy (Standard BT)<br>Standard BT: This group will follow a traditional model of initiating exercise concurrently with a dietary intervention for weight loss within an 18 month behavioral weight loss program. | Behavioral: Standard BT<br>* Both study arms (Standard BT and Sequential BT) will receive an identical 6 month group-based weight loss program, followed by an identical 6 month group-based weight maintenance program, followed by an identical 6 months of weight maintenance phone support. Both groups will also receive an identical 6 month exercise intervention. Groups will differ only in the timing of exercise initiation. Standard BT will begin exercise immediately upon starting the 6 month dietary weight loss intervention. They will receive a progressive exercise program and exercise behavior support during months 0-6.<br>|
| Experimental: Sequential Behavioral Therapy (Sequential BT)<br>Sequential BT: This group will receive diet and exercise interventions delivered sequentially within an 18 month behavioral weight loss program. | Behavioral: Sequential BT<br>* Both study arms (Standard BT and Sequential BT) will receive an identical 6 month group-based weight loss program, followed by an identical 6 month group-based weight maintenance program, followed by an identical 6 months of weight maintenance phone support. Both groups will also receive an identical 6 month exercise intervention. Groups will differ only in the timing of exercise initiation. Sequential BT will be asked not to begin exercise during months 0-6. They will receive a progressive exercise program and exercise behavior support during months 7-12.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in Body Weight | Body weight will be assessed. | Baseline, 3, 6, 9, 12, 15, and 18 months. | 
| Change in Body Composition | Body composition will be assessed. | Baseline, 6, 12, and 18 months. | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Objectively Measured Change in Physical Activity | Physical activity will be measured with activity monitors. | Baseline, 6, 12, and 18 months. | 
| Change in Maximal Aerobic Capacity | Maximal aerobic capacity will be measured. | Baseline, 6, 12, and 18 months. | 
| Change in Diet Composition | Dietary energy intake (calories/day) and fat intake (grams/day) will be measured. | Baseline, 6, 12, and 18 months. | 
| Change in Engagement in Weight Control Eating Behaviors | Engagement in weight control eating behaviors will be measured with a questionnaire. | Baseline, 6, 12, and 18 months. | 
| Change in Dietary Weight Loss Program Attendance and Adherence | Dietary weight loss program attendance and adherence will be assessed throughout the 18 month program. | 18 months | 
| Change in Exercise Program Attendance and Adherence | Exercise program attendance and adherence will be assessed throughout the 18 month program. | 18 months | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Obesity, weight-loss, Physical activity