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

NCT ID: NCT03499509

Last Updated: 2025-05-18

Basic Information

• Recruitment Status: COMPLETED
• Clinical Phase: NA
• Total Enrollment: 67 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2019-03-19
• Study Completion Date: 2024-04-30

Brief Summary

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.

Conditions

Diet Modification

Study Design

• Allocation Method: RANDOMIZED
• Intervention Model: PARALLEL
• Primary Study Purpose: TREATMENT
• Blinding Strategy: NONE

Study Groups

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.

Group Type: EXPERIMENTAL

Low Glycemic Diet

Intervention Type: OTHER

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.

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.

Group Type: PLACEBO_COMPARATOR

High Glycemic Diet

Intervention Type: OTHER

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.

Interventions

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.

Intervention Type: 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.

Intervention Type: OTHER

Other Intervention Names

Low Carbohydrate Diet; Low Fat Diet

Eligibility Criteria

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.

• Minimum Eligible Age: 19 Years
• Maximum Eligible Age: 65 Years
• Eligible Sex: FEMALE
• Accepts Healthy Volunteers: Yes

Sponsors

National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)

NIH

Sponsor Role: collaborator

University of Alabama at Birmingham

OTHER

Sponsor Role: lead

Responsible Party

Barbara Gower

Professor

Responsibility Role: PRINCIPAL_INVESTIGATOR

Principal Investigators

Barbara Gower, PhD

Role: PRINCIPAL_INVESTIGATOR

The University of Alabama at Birmingham

Locations

The University of Alabama at Birmingham

Birmingham, Alabama, United States

Countries

United States

References

Lopez Torres SY, Gower BA, Garvey WT, Martins C. Adaptive Thermogenesis After Hypocaloric Low-Carbohydrate Versus Low-Fat Diets in African American Women: A Secondary Analysis. Obesity (Silver Spring). 2025 Sep 10. doi: 10.1002/oby.70020. Online ahead of print.

Reference Type: DERIVED

PMID: 40931394 (View on PubMed)

Provided Documents

Document Type: Study Protocol and Statistical Analysis Plan

View Document

Other Identifiers

R01DK115483-01A1

Identifier Type: NIH

Identifier Source: secondary_id

View Link

IRB-300001324

Identifier Type: -

Identifier Source: org_study_id