To test adaptive intensive behavioral therapy strategies comprising dietary patterns with varying amounts of protein and including supplemental protein or resistance exercise training for promoting weight loss and attenuating lean mass loss in adults aged 50-75 with obesity.
This Sequential Multiple Assignment Randomized Trial (SMART) seeks to identify the optimal initial dietary strategy (high vs. standard protein diets) and as-needed augmentation strategy (protein supplementation vs. supervised resistance exercise training) for behavioral weight loss in adults aged 50-75. Augmentation strategies will only be used for participants who do not achieve at least 3% weight loss and/or those who lose more than 1.5 kg of fat free mass (i.e., Non-Responders) after 8 weeks of group-based behavioral obesity treatment. Protein supplements and supervised resistance exercise training will be provided at no-cost to participants for weeks 9-16 of the study. Responders (i.e., achieving at least 3% weight loss and less than 1.5 kg loss of fat free mass) will continue with their initial high protein or standard protein diet assignment for the remainder of the trial. This SMART will enroll 250 adults aged 50-75 years with a BMI of at least 30 kg/m2. All participants will receive 1 year of behavioral obesity treatment including 16 weeks of weekly group-based treatment (active weight loss phase) followed by 36 weeks of monthly group sessions to promote continued engagement in dietary and exercise behaviors and long-term weight loss maintenance. The behavioral intervention will be delivered via Zoom. Data collection will occur at the University of Alabama at Birmingham and 5 study visits will be scheduled including: screening (to determine eligibility), prior to starting the weight loss intervention (baseline), and at weeks 8, 16, and 52.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
DOUBLE
Enrollment
250
16 week group-based weight loss program with counseling to consume a high protein diet. Approximate macronutrient distributions (carbohydrate:protein:fat) will be 32%:40%:28%.
16 week group-based weight loss program with counseling to consume a standard protein diet. Approximate macronutrient distributions (carbohydrate:protein:fat) will be 53%:20%:27%.
Non-responders from either initial randomized group assigned to this intervention receive twice daily protein supplements.
University of Alabama at Birmingham
Birmingham, Alabama, United States
Change in Body Weight
Participants will be weighed at baseline through 52 weeks
Time frame: Baseline, 8 weeks, 16 weeks, 52 weeks
Change in Fat Free Mass
Participants will be scanned via DXA scan to measure overall fat free body mass
Time frame: Baseline, 8 weeks, 16 weeks, 52 weeks
Change in Fat Mass
Participants will be scanned via DXA scan to measure overall fat mass
Time frame: Baseline, 8 weeks, 16 weeks, 52 weeks
Change in Fasting Glucose
Participants will have a blood draw to check fasting blood sugar levels
Time frame: Baseline, 8 weeks, 16 weeks, 52 weeks
Change in Fasting Insulin
Participants will have a blood draw to check fasting insulin levels
Time frame: Baseline, 8 weeks, 16 weeks, 52 weeks
Change in Fasting Hemoglobin A1C
Participants will have a blood draw to check fasting A1C levels
Time frame: Baseline, 8 weeks, 16 weeks, 52 weeks
Change in Fasting LDL-cholesterol
Participants will have a blood draw to check fasting LDL-cholesterol levels
Time frame: Baseline, 8 weeks, 16 weeks, 52 weeks
Change in Fasting HDL-cholesterol
Participants will have a blood draw to check fasting HDL-cholesterol levels
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Non-responders from either initial randomized group assigned to this intervention receive twice weekly small-group supervised resistance exercise training sessions.
Time frame: Baseline, 8 weeks, 16 weeks, 52 weeks
Change in Fasting Total Cholesterol
Participants will have a blood draw to check fasting total cholesterol levels
Time frame: Baseline, 8 weeks, 16 weeks, 52 weeks
Change in Fasting Total Triglycerides
Participants will have a blood draw to check fasting triglyceride levels
Time frame: Baseline, 8 weeks, 16 weeks, 52 weeks
Change in Blood Pressure
Participants will have a blood pressure check at each appointment
Time frame: Baseline, 8 weeks, 16 weeks, 52 weeks
Change in Hand Grip Strength
Participants will have hand grip strength via the Jamar dynamometer, a tool for assessing and monitoring patients' hand strength. Measurements are based on a scale of 0-90 kilograms of force, where higher numbers indicate more strength.
Time frame: Baseline, 8 weeks, 16 weeks, 52 weeks
Change in Lower Extremity Strength
Participants will be assessed using the Short Physical Performance Battery (SPPB). The SPPB is a commonly-used assessment of lower extremity function in aging adults and used a combined score comprising tests of balance, gait speed, and the chair stand test. Key Components and Scoring (0-12 points total): Standing Balance: Evaluates three stances (side-by-side, semi-tandem, tandem) held for 10 seconds each, scored up to 4 points. Gait Speed: Measures the time taken to walk 3 or 4 meters at a normal pace, scored up to 4 points. Chair Stands: Measures the time taken to rise from a chair five times without using arms, scored up to 4 points. Interpretation and Cut-off Scores: Total Score 0-6: Indicates low performance and high risk for functional decline. Total Score 7-9: Moderate performance. Total Score 10-12: High performance.
Time frame: Baseline, 8 weeks, 16 weeks, 52 weeks