Balanced (Egg) Protein During Obesity Reduction: Differential Responses of Insulin Resistance by Race

Balanced (Egg) Protein During Obesity Reduction: Differential Responses of Insulin Resistance by Race

The purpose of the trial is to assess the effects of combining regular, generous intakes of high quality protein (with substantial amounts provided from whole eggs and egg whites) with calorie restriction on insulin resistance and weight loss (along with function, body composition, racial disparities, and a number of secondary outcomes) in black and white older adults with prediabetes who are participating in a 4-month intervention. The investigators will compare these effects to the same outcomes with a control group consuming a traditional control regimen of calorie restriction over the same duration.

Older (>60 yrs) men and women (50% African American, 50% white) who are obese (BMI >30 kg/m2) and have pre-diabetes will be randomly assigned (1:1 ratio; couples randomized together) to one to two treatment groups: 1) Weight loss intervention (WL-Control; n = 20): subjects follow a calorie-reduction diet for a weight loss of ≥10%, protein~0.8g/g/d; and 2) High protein weight loss intervention (WL-Protein; n = 20): subjects follow a calorie-reduction diet for a weight loss of ≥10%, with a high proportion of high quality protein (> 30g protein, 3/day, 60-70% egg protein). Primary (insulin resistance/sensitivity, weight loss) and secondary outcomes (physical function, body composition, diet adherence, cognitive function, readiness to change) will be measured at 0 and 4 months.

Inclusion Criteria:

• Age > 60 years
• Identifies as Caucasian/white or African-American/black
• Obese body weight (>30 kg/m2)
• Able to speak and understand spoken and written English
• Elevated fasting plasma glucose (≥95 and <126 mg/dL)
• Age-normal Kidney function (≥ 45 mL/min/1.73 m2)

Exclusion Criteria:

• Body weight > 224 kg (limit of the BodPod)
• Treated or untreated diabetes (prior diagnosis, treatment, or fasting blood glucose ≥126 mg/dL)
• Presence of unstable, acutely symptomatic, or life-limiting illness
• Positive screen for dementia using Mini-Cog evaluation tool
• Neurological conditions causing functional or cognitive impairments
• History of significant weight instability (defined as > 10 pounds weight gain or loss over 6 months prior to study participation)
• Allergy or intolerance to egg products
• Unwillingness or inability to be randomized to any one of two intervention groups, submit to all study testing, or continuously participate in a randomly assigned lifestyle intervention program for four months
• Inability to walk independently
• Unable to give consent
• Unable to complete written recording forms including journals of eating and exercise behaviors.
• Current use of the following medications: monoamine oxidase inhibitors, prescription weight loss medications, insulin, metformin or any other hypoglycemic agent
• Primary Care Physician advises against participation
• Smoker
• Unusually or unstable renal function