Obesity
Conditions
Keywords
weight loss, dietary protein, exercise training, fat free mass
Brief summary
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).
Interventions
BEHAVIORALHigh Protein Diet
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.
BEHAVIORALResistance Training
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.
Sponsors
University of Alabama at Birmingham
Study design
Allocation
RANDOMIZED
Intervention model
SEQUENTIAL
Primary purpose
OTHER
Masking
NONE
Eligibility
Sex/Gender
ALL
Age
50 Years to No maximum
Healthy volunteers
Yes
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.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| 2nd Stage Treatment Credibility | Week 8. | Perceived credibility of 2nd stage interventions will be measured in non-responders to 1st stage interventions at week 8 with the Credibility/Expectancy Questionnaire. |
| 1st Stage Intervention Preference | Baseline | 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. |
| 2nd Stage Intervention Preference | Week 8 | 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. |
| Recruitment and Retention Rates | Baseline through week 52. | Rates of study recruitment and retention will be tracked to determine clinical trial feasibility. |
| Class Attendance | Baseline through week 52. | Class Attendance will be tracked to determine clinical trial feasibility. |
| 1st Stage Treatment Credibility | Baseline. | Perceived credibility of 1st stage interventions will be measured at baseline with the Credibility/Expectancy Questionnaire. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Body Weight | Baseline, Weeks 8, 16, and 52 | Changes from baseline body weight will be measured at weeks 8, 16, and 52. |
| Fat mass | Baseline, Weeks 8, 16, and 52 | Changes from baseline fat mass will be measured at weeks 8, 16, and 52. |
| Fat free mass | Baseline, Weeks 8, 16, and 52 | Changes from baseline fat free mass will be measured at weeks 8, 16, and 52. |
Other
| Measure | Time frame | Description |
|---|---|---|
| Change in glucose | Baseline to Weeks 8, 16, and 52 | Serum glucose will be measured in a fasted state and after a glucose load \[mg/dL\] |
| Change in insulin | Baseline to Weeks 8, 16, and 52 | Serum insulin will be measured in a fasted state and after a glucose load, measured in micro-units/milliliter \[uU/mL\] |
| Changes in lipids | Baseline to Weeks 8, 16, and 52 | Fasting serum concentrations of total cholesterol, LDL cholesterol, HDL cholesterol, and triglycerides |
| Changes in disposition index | Baseline to Weeks 8, 16, and 52 | Derived from Oral Glucose Tolerance Test (OGTT) using 0 minute and 30 minute time-points. |
| Changes in aerobic fitness | Baseline to Weeks 8, 16, and 52 | 6-Minute Walk test for ambulatory participants OR 6-Minute Push test for wheelchair users. |
| Changes in physical activity | Baseline to Weeks 8, 16, and 52 | 7-day accelerometry |
Countries
United States
Outcome results
None listed