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

Purpose

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.

Condition

  • Diet Modification

Eligibility

Eligible Ages
Between 19 Years and 65 Years
Eligible Sex
Female
Accepts Healthy Volunteers
Yes

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 Design

Phase
N/A
Study Type
Interventional
Allocation
Randomized
Intervention Model
Parallel Assignment
Primary Purpose
Treatment
Masking
None (Open Label)

Arm Groups

ArmDescriptionAssigned Intervention
Experimental
Low Glycemic Diet 		Low Glycemic (LG) diet: The LG diet was made up of foods that do not stimulate insulin secretion and was composed of 20% CHO, 55% fat, and 25% protein. The diet emphasized complex over simple carbohydrates and allowed dairy products, fruits, and vegetables within allowance of the diet.
  • Other: Low Glycemic Diet
    Low Glycemic (LG) diet: The LG diet was made up of foods that do not stimulate insulin secretion and was composed of 20% CHO, 55% fat, and 25% protein. The diet emphasized complex over simple carbohydrates and allowed dairy products, fruits, and vegetables within allowance of the diet.
    Other names:
    • Low Carbohydrate Diet
Placebo Comparator
High Glycemic Diet 		High Glycemic (HG) diet: The HG diet aligned with the United States Department of Agriculture (USDA) guidelines (http://health.gov/dietaryguidelines/2015/guidelines/) and was composed of 55% CHO, 20% fat, and 25% protein. The diet emphasized complex over simple carbohydrates and allowed dairy products, fruits, and vegetables within allowance of the diet.
  • Other: High Glycemic Diet
    High Glycemic (HG) diet: The HG diet aligned with the United States Department of Agriculture (USDA) guidelines (http://health.gov/dietaryguidelines/2015/guidelines/) and was composed of 55% CHO, 20% fat, and 25% protein. The diet emphasized complex over simple carbohydrates and allowed dairy products, fruits, and vegetables within allowance of the diet.
    Other names:
    • Low Fat Diet

More Details

Status
Completed
Sponsor
University of Alabama at Birmingham

Study Contact