Use of a Soy-based Meal Replacement Weight Loss Intervention to Impact Ectopic Fat and Associated Cardio-metabolic Risk in Obese, Older Adults: A Feasibility Study

The main objectives of this study are to collect pilot data to assess feasibility (accrual, retention, compliance), to estimate the variability of outcome measures, and to obtain preliminary estimates of treatment efficacy based on group differences in body composition (decreases in ectopic fat stores while maintaining lean mass), cardio-metabolic risk factors including glucoregulatory function (glucose, insulin), inflammation (C-reactive protein, IL-6), blood pressure and lipids (HDL, LDL, TC, TG), and measures of physical function and muscle strength. While this is just a pilot study, randomization will be used so that the investigators can obtain a realistic estimate of accrual (which is often less in a randomized trial) and an unbiased estimate of treatment efficacy. The investigators will accomplish these objectives by conducting a 2-arm, 3-month randomized, clinical trial in 24 older (60-79), abdominally obese (BMI ≥30 kg/m2 and waist circumference ≥ 102 cm and ≥ 88 cm in men and women, respectively) men and women. Participants will be randomized to a soy-based or animal-based, 3-month, hypocaloric dietary intervention to achieve our specific aims: Primary Aim: To determine our ability to recruit and retain older, obese adults to a 3 month soy-based meal replacement weight loss intervention and assess the study participant's ability to adhere to the intervention protocol (weight, compliance logs, serum isoflavones). Secondary Aims: 1. To estimate the variability of and obtain preliminary estimates of the effect of the soy-based meal replacement on measures of body composition, including abdominal (total, subcutaneous and visceral fat), liver, and pericardial fat; anthropometrics (body weight, waist/hip circumference); and whole body fat and lean mass. 2. To estimate the variability of and obtain preliminary estimates of the effect of the soy-based meal replacement on biomarkers of cardiometabolic risk including glucoregulatory function (glucose, insulin), inflammation (C-reactive protein, IL-6), blood pressure and lipids (HDL, LDL, TC, TG). 3. To estimate the variability of and obtain preliminary estimates of the effect of the soy-based meal replacement on physical function (short physical performance battery, 400-m walk) and muscle strength (grip and knee extensor strength) and size (CT thigh muscle). 4. To document any adverse events associated with the soy-based meal replacement.