Diet Modification
Conditions
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.
Interventions
OTHERLow 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.
OTHERHigh 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.
Sponsors
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
University of Alabama at Birmingham
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
NONE
Eligibility
Sex/Gender
FEMALE
Age
19 Years to 65 Years
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.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Total Energy Expenditure | 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. |
Countries
United States
Participant flow
Participants by arm
| Arm | Count |
|---|---|
| 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. | 34 |
| 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. | 33 |
| Total | 67 |
Baseline characteristics
| Characteristic | Low Glycemic Diet | High Glycemic Diet | Total |
|---|---|---|---|
| Age, Categorical <=18 years | 0 Participants | 0 Participants | 0 Participants |
| Age, Categorical >=65 years | 0 Participants | 0 Participants | 0 Participants |
| Age, Categorical Between 18 and 65 years | 34 Participants | 33 Participants | 67 Participants |
| Race (NIH/OMB) American Indian or Alaska Native | 0 Participants | 0 Participants | 0 Participants |
| Race (NIH/OMB) Asian | 0 Participants | 0 Participants | 0 Participants |
| Race (NIH/OMB) Black or African American | 34 Participants | 33 Participants | 67 Participants |
| Race (NIH/OMB) More than one race | 0 Participants | 0 Participants | 0 Participants |
| Race (NIH/OMB) Native Hawaiian or Other Pacific Islander | 0 Participants | 0 Participants | 0 Participants |
| Race (NIH/OMB) Unknown or Not Reported | 0 Participants | 0 Participants | 0 Participants |
| Race (NIH/OMB) White | 0 Participants | 0 Participants | 0 Participants |
| Sex: Female, Male Female | 34 Participants | 33 Participants | 67 Participants |
| Sex: Female, Male Male | 0 Participants | 0 Participants | 0 Participants |
Adverse events
| Event type | EG000 affected / at risk | EG001 affected / at risk |
|---|---|---|
| deaths Total, all-cause mortality | 0 / 34 | 0 / 33 |
| other Total, other adverse events | 0 / 34 | 0 / 33 |
| serious Total, serious adverse events | 0 / 34 | 0 / 33 |
Outcome results
Primary
Total Energy Expenditure
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.
Time frame: Baseline, Week 13
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| Low Glycemic Diet | Total Energy Expenditure | Baseline | 2411 kcal/day | Standard Deviation 342 |
| Low Glycemic Diet | Total Energy Expenditure | week 13 | 2318 kcal/day | Standard Deviation 362 |
| High Glycemic Diet | Total Energy Expenditure | Baseline | 2316 kcal/day | Standard Deviation 289 |
| High Glycemic Diet | Total Energy Expenditure | week 13 | 2179 kcal/day | Standard Deviation 413 |