Utilizing Protein During Weight Loss to Impact Physical Function

Not Applicable

Completed

Conditions: Weight Loss
Obesity
Aging
Dietary Habits
Diet Modification
Weight Change, Body

Registration Number: NCT03074643

Lead Sponsor: Wake Forest University Health Sciences

Brief Summary: This study will evaluate the effects of diet composition (i.e., amount of protein and carbohydrate) during a 6-month weight loss intervention and 12-months of follow-up on physical function, muscle mass, and weight loss maintenance in obese older adults. Participants will receive either a protein or carbohydrate supplement along with a behavioral weight loss intervention.

Detailed Description: The study will use a 3-group design in 225 obese (BMI 27-45 kg/m2), older (65-85 years) men and women at risk for disability (eSPPB \<2.5) who will undergo a 6-month weight loss intervention followed by a 12-month follow-up phase to test the overall hypothesis that a higher protein (1.2 g/kg body wt/d) / lower carbohydrate (CHO) diet during a 6-month weight loss intervention improves physical function compared with an isocaloric lower protein (the current Recommended Dietary Allowance (RDA), 0.8 g/kg body wt/d) / higher CHO diet, and whether continuing a higher protein / lower CHO diet for 12-months following weight loss will result in better maintenance of improved physical function. All participants will undergo a 6-month weight loss intervention involving caloric restriction and supervised exercise followed by 12 months of follow-up with randomization to one of three groups (n=75/group): 1) Lower protein / higher CHO diet for the 6-month weight loss phase only (RecProt); 2) Higher protein / lower CHO diet for the 6-month weight loss phase only (6-mo HiProt); or 3) Higher protein / lower CHO diet for the 6-month weight loss and 12-month follow-up phases (18-mo HiProt). Physical function (primary aim) will be assessed by the expanded Short Physical Performance Battery (primary outcome) and lower extremity muscle strength at baseline, 6-, 12- and 18-months. Weight loss maintenance and body composition (secondary aim) will be assessed by dual-energy X-ray absorptiometry (DXA) and computed tomography (CT) at baseline, 6- and 18-months. Bone mineral density (DXA) and cardiometabolic risk factors will also be measured at baseline, 6- and 18-months.

Recruitment & Eligibility

Status: COMPLETED

Sex: All

Target Recruitment: 187

Inclusion Criteria

65-85 years
BMI: 27-45 kg/m2
No regular resistance training and/or aerobic exercise (>20 mins/d) for past 6 months
eSPPB <2.5
No contraindications for safe and optimal participation in exercise training
Approved for participation by Medical Director (Dr. Lyles)
Willing to provide informed consent
Agree to all study procedures and assessments
Willing to consume protein/CHO supplements for up to 18 months
Able to provide own transportation to study visits and intervention sessions

Exclusion Criteria

Weight loss (≥5%) in past 6 months
Dependent on cane or walker
Cognitive impairment (MoCA score <22)
Severe arthritis, or other musculoskeletal disorder
Joint replacement or other orthopedic surgery in past 6 months
Uncontrolled resting hypertension (>160/90 mmHg);
Insulin-dependent or uncontrolled diabetes (HbA1c ≥8%)
Current or recent past (within 1 year) severe symptomatic heart disease, uncontrolled angina, stroke, chronic respiratory disease requiring oxygen; uncontrolled endocrine/metabolic disease; neurological or hematological disease; cancer requiring treatment in past year, except non-melanoma skin cancers; liver or renal disease; or clinically evident edema
Unstable, severe depression
Serious conduction disorder, uncontrolled arrhythmia, or new Q waves or ST-segment depressions (>3 mm at rest or ≥2 mm with exercise)
Abnormal kidney function (eGFR <30 based on serum creatinine, age, gender, and race)
Anemia (Hb<13 g/dL in men; <12 g/dL in women)
Drug abuse or excessive alcohol use (>7 drinks/week women; >14 drinks/week men)
Use of any tobacco or nicotine products in the past year
Osteoporosis (T-score < -2.5 on hip or spine scan)
Regular use of growth/steroid hormones, sex steroids or corticosteroids, osteoporosis medication, or protein supplements
Weight loss medications or procedures
Current participation in another intervention study

Study & Design

Study Type: INTERVENTIONAL

Study Design: PARALLEL

Primary Outcome Measures

Name	Time	Method
Change in Expanded Short Physical Performance Battery Score	18 months	To determine the effects of a higher protein / lower CHO diet vs. lower protein / higher CHO diet during a 6-month weight loss intervention and 12 months of follow-up on change in lower extremity physical function assessed by the expanded Short Physical Performance Battery score over 18 months. The expanded Short Physical Performance Battery score ranges from 0 to 4 with higher scores indicating better lower extremity physical function

Secondary Outcome Measures

Name	Time	Method
Intermuscular Adipose Tissue	18 months	To determine the effects of a higher protein / lower CHO diet vs. lower protein / higher CHO diet during a 6-month weight loss intervention and 12 months of follow-up on change in computerized tomography (CT) acquired thigh intermuscular adipose tissue over 18 months
Lower Extremity Muscle Strength	18 months	To determine the effects of a higher protein / lower CHO diet vs. lower protein / higher CHO diet during a 6-month weight loss intervention and 12 months of follow-up on change in lower extremity muscle strength assessed using an isokinetic dynamometer (Biodex) over 18 months
Weight Change	18 months	To determine the effects of a higher protein / lower CHO diet vs. lower protein / higher CHO diet during a 6-month weight loss intervention and 12 months of follow-up on change in body weight over 18 months
Thigh Muscle Volume	18 months	To determine the effects of a higher protein / lower CHO diet vs. lower protein / higher CHO diet during a 6-month weight loss intervention and 12 months of follow-up on change in computerized tomography (CT) acquired thigh muscle volume over 18 months
Total Body Lean Mass	18 months	To determine the effects of a higher protein / lower CHO diet vs. lower protein / higher CHO diet during a 6-month weight loss intervention and 12 months of follow-up on change in dual energy x-ray (DXA) acquired total body lean mass over 18 months
Total Body Fat Mass	18 months	To determine the effects of a higher protein / lower CHO diet vs. lower protein / higher CHO diet during a 6-month weight loss intervention and 12 months of follow-up on change in dual energy x-ray acquired (DXA) total body fat mass over 18 months

Trial Locations

Locations (1): Geriatric Research Center at Wake Forest Baptist Health
🇺🇸
Winston-Salem, North Carolina, United States
Geriatric Research Center at Wake Forest Baptist Health
🇺🇸Winston-Salem, North Carolina, United States