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.

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Key information

Conditions

Diet Modification

Age range

19 year–65 year

Sex eligibility

Female

Study type

Interventional

Phase

Not applicable

Primary location

The University of Alabama at Birmingham

Birmingham, Alabama, 35294, United States

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

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.

Treatment and study plan

Low glycemic diet

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.

Other names: Low Carbohydrate Diet

High Glycemic Diet

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.

Other names: Low Fat Diet

Primary outcomes

Total Energy Expenditure

Time frame: Baseline, Week 13

Total energy expenditure measured by doubly labeled water. The protocol is based on established procedures [12]. Urine samples are analyzed in duplicate for H218O and 2H2O enrichments using Thermo Scientific Delta V Advantage IRMS with GasBench. CO2 production rates are determined using a fixed assumption for the dilution space ratio (1.043), using Equation 3 of Speakman et al. [10], and energy expenditure is calculated with equation 5 of Speakman et al. [10].

[10] Speakman JR, Yamada Y, Sagayama H et al. A standard calculation methodology for human doubly labeled water studies. Cell Rep Med 2021; 2:100203.

[12] Goran MI, Carpenter WH, McGloin A et al. Energy expenditure in children of lean and obese parents. American Journal of Physiology 1995; 31:E917-E924.

[13] Wolfe RR. Measurement of Total Energy Expenditure Using the Doubly-Labeled Water Method. In: Radioactive and Stable Isotope Tracers in Biomedicine. Edited by: Wiley-Liss. 1992.

Sponsors and collaborators

Lead sponsor

University of Alabama at Birmingham

Other

Collaborators

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

Registry information

Acronym: CHAMPION

Important dates

Study start: 2019
Primary completion: 2024
Study completion: 2024
First posted: Apr 17, 2018
Registry last updated: May 18, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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