Obesity Risk in African American Women is Determined by a Diet-by-phenotype Interaction

The Scientific Premise of this study is that the high level of obesity displayed by African American (AA) women is due to the ability to secrete large amounts of insulin when sugary foods are consumed. When AA women eat a diet rich in starchy or sugary food (a "high-glycemic" diet that stimulates insulin secretion), the food that is eaten is stored as fat rather than being burned as fuel. The investigators previous research has suggested that AA women have an easier time losing weight and keeping it off when eating a low-glycemic diet. The proposed study will be the first randomized clinical trial to test the effect of high and low glycemic diets for weight loss and weight-loss-maintenance in obese AA women.

Study Overview

• Status: Active, not recruiting
• Conditions: Diet Modification
• Intervention / Treatment: Other: Low Glycemic Diet; Other: High Glycemic Diet

• Study Type: Interventional
• Enrollment (Actual): 69
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Adrienna Stephens; Phone Number: 205-975-6579; Email: as1217@uab.edu
• Study Contact Backup: Name: Laura Lee Goree; Phone Number: 205-934-4386; Email: LLG@uab.edu

Study Locations

• United States
  • Alabama
    • Birmingham, Alabama, United States, 35294
      • The University of Alabama at Birmingham

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 19 years to 65 years (Adult, Older Adult)
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• BMI 30-45 kg/m2
• Sedentary to moderately active (<2 hours/wk of moderate, structured, intentional exercise.
• Normal menstrual cycle

Exclusion Criteria:

• History of eating disorder
• daily use of tobacco (>1 pack/wk)
• change in weight greater than 5 pounds in previous 3 months
• presence of any condition (e.g. PCOS) or use of any medication (e.g. glucocorticoid) deemed by the project physician to interfere with study outcomes
• applicants will be screened with a standard oral glucose tolerance test. If a participant's 2 hour glucose if >200, they will not be able to enroll in the study.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Low Glycemic Diet	Other: Low Glycemic Diet; Low Glycemic (LG) diet: The LG diet will be made up of foods that do not stimulate insulin secretion. The foods that make up the diet will differ depending on the phase of the study. During the weight loss phase, breakfast and lunch will each consist of one or two meal-replacement "shakes" (e.g., High-Protein SlimFast). Dinner will be a frozen entrée (e.g., Atkins, Lean Cuisine, Healthy Choice) supplemented with a side of vegetables. Snacks will be nuts, berries, and full-fat dairy products (one serving per day), and will be used to adjust the calorie level of each day's meals to individual calorie needs.
Placebo Comparator: High Glycemic Diet	Other: High Glycemic Diet; High Glycemic (HG) diet: The HG diet will conform to United States Department of Agriculture (USDA) guidelines (http://health.gov/dietaryguidelines/2015/guidelines/). The foods that make up the diet will differ depending on the phase of the study. During the weight loss phase, breakfast and lunch will each consist of one or two meal-replacement "shakes" (e.g., SlimFast). Dinner will be a frozen entrée (e.g., Lean Cuisine, Healthy Choice) supplemented with a side of vegetables. Snacks will be fruit, fat-free dairy products, and low-fat bars (e.g., Optifast), and will be used to adjust the calorie level of each day's meals to individual calorie needs.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Body composition	Body composition will be measured using Dual Energy X-Ray Absorptiometry (DXA) scan.	10 months
Resting energy expenditure	Resting energy expenditure will be measured by indirect calorimetry.	10 months
Total energy expenditure	Total energy expenditure will be measured by doubly labeled water.	4 months
Metabolic efficiency	Metabolic efficiency will be measured by submaximal exercise test.	4 months

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Self-reported adherence of each diet	Self-reported adherence of each diet will be measured by interview.	10 months

Collaborators and Investigators

• Sponsor: University of Alabama at Birmingham

Study record dates

Study Major Dates

• Study Start (Actual): March 19, 2019
• Primary Completion (Estimated): July 31, 2024
• Study Completion (Estimated): July 31, 2024

Study Registration Dates

• First Submitted: April 4, 2018
• First Submitted That Met QC Criteria: April 13, 2018
• First Posted (Actual): April 17, 2018

Study Record Updates

• Last Update Posted (Actual): April 8, 2024
• Last Update Submitted That Met QC Criteria: April 4, 2024
• Last Verified: April 1, 2024

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Overnutrition; Nutrition Disorders; Overweight; Body Weight; Obesity
• Other Study ID Numbers: R01DK115483-01A1 (U.S. NIH Grant/Contract)

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No