Veterans Achieving Weight Loss and Optimizing Resilience-Using Protein

Enhanced Protein Intake During Obesity Reduction in Older Male Veterans: Differences in Physical Function and Muscle Quality Responses by Race

Diabetes is a major health concern in obese older Veterans, especially in those who are African American. The negative impact of diabetes on muscle and physical function contributes to metabolic as well as physical decline and is under-studied. This randomized controlled trial compares a higher-protein, weight loss regimen previously shown to improve physical function to an Recommended Dietary Allowance (RDA) protein intervention in obese older male Veterans with pre-diabetes and functional limitations. Equal numbers of white and black male Veterans will be studied, filling gaps in the investigators' knowledge of differential responses by race as well as obesity interventions for men in general. The primary outcome is functional performance by Short Physical Performance Battery and secondary measures include muscle quantity and composition, glucose handling, lean body mass, recent falls and fear of falling, and quality of life measured at 0, 3 and 6 months. The goal of this research is to accelerate functional recovery and enhance independence in obese male Veterans, which is strongly aligned with the VA mission to "maximize the physical and social autonomy of Veterans".

This study examines an evidence-based obesity intervention as a means of reducing the impact of prediabetes on muscle function in obese older men of white and black race. A total of 64 obese (BMI 30 kg/m2) male Veterans aged 55 + yrs, with mild to moderate functional impairments (Short Physical Performance Battery score of 4 to 11 units) and prediabetes, will be randomized to a higher-protein weight loss treatment (HP-WL) or an RDA-level protein control weight loss treatment (C-WL). All participants receive individualized calorie prescriptions calculated to achieve a weight loss of ~1-2 pounds per week and attend weekly group support sessions designed to enhance diet compliance with goal setting, self-monitoring, stress management, and daily diet journaling. They will also attend a weekly low impact, chair exercise class. HP-WL participants are provided a supply of chilled/frozen high-quality protein foods (lean meats, low fat dairy products) sufficient to give 30 g high quality protein for two of three meals daily to help assure diet compliance. C-WL participants are provided 1 serving per day of high quality protein to avoid unintentional bias. Treatment responses will be compared for the primary outcome of functional performance by Short Physical Performance Battery and important secondary measures, including muscle quantity and composition, glucose handling, lean body mass, recent falls and fear of falling, and quality of life at 0, 3 and 6 months. An exploratory aim examines potential mediators of racial differences in treatment responses and documents the most successful intervention strategies. This randomized controlled trial of a balanced, higher-protein diet during a metabolic challenge (caloric restriction) in those with prediabetes also considers racial differences in responses of obese older men to this regimen. Study findings will fulfill the RR&D mission by advancing interventions to improve physical function in older Veterans, yield novel information about the impact of balanced, higher protein on muscle and glucose handling, and explore racial differences in responses to obesity interventions.

Inclusion Criteria:

• Male Veterans
• African American or Caucasian
• Obese (BMI > 30 kg/m2)
• Age 55+ years
• Pre-diabetes (confirmed fasting plasma glucose 100 and <126 mg/dL) or HbA1c 5.7-6.4%
• Short Physical Performance Battery score of 4 to 11 units
• Age-normal renal function
• English speaking
• Able to record dietary intake or has a proxy who can record dietary intake
• Willing and able to be randomized to either intervention group

Exclusion Criteria:

• Presence of unstable or symptomatic life-threatening illness

• Glomerular filtration rates (GFR) less than 45 mL/min

  • A GFR of 45-59 requires bi-monthly testing per the investigators' established algorithm
  • Those with a GFR <45 mL/min are excluded

• Mini Cog score of <3

  --Vegetarian

• Neurological conditions causing functional impairments, including:

  • Parkinson's Disease
  • multiple sclerosis
  • permanent disability due to stroke

• Inability to complete physical function assessment

• History of significant weight instability

• Contraindicated medications, including narcotic mail-outs and active substance abuse

• Any psychiatric condition that would prevent the subject from participating in a group intervention setting, including diagnosed personality disorders

• Primary care provider disapproves participation