Weight Loss in Adults Over 50 With Obesity

Study Overview
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Brief Summary
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The purpose of this study is to examine the separate and combined effects of a high-protein (HP) diet and resistance training (RT) on body composition and potential biological moderators of body weight in women and men >50y. All participants will receive dietary physical activity guidance through our group-based weight loss program, State of Slim (SOS). The SOS program will be delivered via the Zoom videoconferencing platform. These participants will be randomized to receive either a counseling-based HP diet plan or RT plan. Body composition assessments at 8 wk will identify responders and non-responders; the latter will be re-randomized to augment (HP: add protein supplements; RT: supervise RT) or combine (HP with protein supplements + supervised RT).

Official Title
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Effects of Dietary Protein Intake and Resistance Training on Retention of Fat Free Mass During Weight Loss in Adults Over 50 With Obesity

Conditions
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Obesity

Intervention / Treatment
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* Behavioral: High Protein Diet
* Behavioral: Resistance Training


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Male or Female Age ≥50 years Post-menopausal if Female BMI of 30-50 kg/m2 for ambulatory participants (less than or equal to 350 lbs.) BMI of 25-50 kg/m2 for wheelchair users (less than or equal to 350 lbs.) Ambulatory with or without a walking device or use of a manual wheelchair for mobility. Exclusion Criteria: Untreated hyper or hypothyroidism. Cancer (except basal cell). Gastrointestinal disorders affecting food intake. <3 months of stable use of medications that affect metabolism, body weight, energy expenditure or appetite. Current eating disorder (e.g., binge eating disorder, anorexia, or bulimia). Any medical condition for which following a HP diet and/or 70 minutes of exercise daily would be inadvisable. Uses a powered wheelchair for mobility. Has a pacemaker or any other life-sustaining medical implant.

Ages Eligible for Study
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Minimum Age: 50 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: Other
Allocation: Randomized
Intervention Model: Sequential Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: High Protein Diet<br>Enrollment in State of Slim (SOS) weight loss program with a high protein diet. | Behavioral: High Protein Diet<br>* 16 week group-based weight loss program with high protein diet. Approximate macronutrient distributions (carbohydrate:protein:fat) will be 32%:40%:28%. Because this protocol uses a sequential, multiple assignment, randomized trial (SMART) design, response will be assessed after 8 weeks. Non-responders will be randomized to either combine the HP diet with supervised resistance training counseling (2 days per week) or add a protein supplement.<br>|
| Experimental: Resistance Training<br>Enrollment in State of Slim (SOS) weight loss program with resistance training counseling sessions. | Behavioral: Resistance Training<br>* 16 week weight loss program with normal protein diet and resistance training counseling. Approximate macronutrient distributions (carbohydrate:protein:fat) will be 53%:20%:26%. Because this protocol uses a sequential, multiple assignment, randomized trial (SMART) design, response will be assessed after 8 weeks. Non-responders will be randomized to either combine resistance training with HP/protein supplement or add supervised sessions with a personal trainer (2 days per week) to the resistance training regimen.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Recruitment and Retention Rates | Rates of study recruitment and retention will be tracked to determine clinical trial feasibility. | Baseline through week 52. | 
| Class Attendance | Class Attendance will be tracked to determine clinical trial feasibility. | Baseline through week 52. | 
| 1st Stage Treatment Credibility | Perceived credibility of 1st stage interventions will be measured at baseline with the Credibility/Expectancy Questionnaire. | Baseline. | 
| 2nd Stage Treatment Credibility | Perceived credibility of 2nd stage interventions will be measured in non-responders to 1st stage interventions at week 8 with the Credibility/Expectancy Questionnaire. | Week 8. | 
| 1st Stage Intervention Preference | Participant preferences for 1st stage interventions will be measured at baseline by answering a 5-point Likert question with '1' and '5' representing a strong preference for either intervention and '3' representing no intervention preference. | Baseline | 
| 2nd Stage Intervention Preference | Participant preferences for 2nd stage interventions will be measured at week 8 by answering a 5-point Likert question with '1' and '5' representing a strong preference for either intervention and '3' representing no intervention preference. | Week 8 | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Body Weight | Changes from baseline body weight will be measured at weeks 8, 16, and 52. | Baseline, Weeks 8, 16, and 52 | 
| Fat mass | Changes from baseline fat mass will be measured at weeks 8, 16, and 52. | Baseline, Weeks 8, 16, and 52 | 
| Fat free mass | Changes from baseline fat free mass will be measured at weeks 8, 16, and 52. | Baseline, Weeks 8, 16, and 52 | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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weight loss, dietary protein, exercise training, fat free mass