Obesity
Conditions
Brief summary
This study will determine the impact of 24, 48 and 72 hours of over and underfeeding on energy expenditure as measured in the metabolic chamber at the UNC Chapel Hill Nutrition Research Institute (UNC NRI).
Detailed description
Subjects will complete a baseline eucaloric study day. Following this, subjects will be randomized to complete 3 days of overfeeding (150% of baseline eucaloric energy requirements) or 3 days of underfeeding (50% of baseline eucaloric energy requirements). After completing one of these study arms, subjects will cross-over and complete the second arm. All study arms will be separated by two weeks. 24-hour energy expenditure will be measured 3 times during each of 3 day periods. We hypothesize that the impact of over or underfeeding on EE will be evident after 24-hours and will be comparable to 72 hour EE.
Interventions
OTHER24-hour energy expenditure
To assess 24-hour energy expenditure and substrate utilization subjects will spend 23 hours and 15 minutes each day in the metabolic chamber at the UNC NRI. Subjects will be requested to arrive at the study center each morning following a 10hour overnight fast. During each study day, subjects remained sedentary. All meals were provided and were tailored to each subject's specific energy requirements and the study protocol (i.e. 50% or 150% of calorie requirements).
Sponsors
University of North Carolina, Chapel Hill
Study design
Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
BASIC_SCIENCE
Masking
NONE
Eligibility
Sex/Gender
FEMALE
Age
50 Years to 65 Years
Healthy volunteers
Yes
Inclusion criteria
* Woman * Postmenopausal * Aged 50-65 years * BMI 25-35kg/m2 * Not taking blood pressure or anti-inflammatory medications or any other medications that may impact the results * Thyroid hormone profile within the normal reference range * No medical condition which may impact the results (e.g. diabetes) * Accustomed to eating regular meals including breakfast
Exclusion criteria
* Smoker * Heavy exerciser (defined as \>150 minutes/week for more than 3 months) * Abuses alcohol or drugs * Vegetarian
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Energy Expenditure | 24-hour energy expenditure will be assessed | 24-hour energy expenditure will be assessed using the metabolic chamber at UNC NRI. Energy expenditure will be measured during eucaloric feeding (subjects will receive 100% of calorie requirements), as well as during 24, 48 and 72 hours of under and overfeeding. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Whole blood transcriptomics | Fasting a.m. sample, before lunch, and at 0.5, 2, and 4.5 hours post lunch | RNA will be extracted from whole blood. Transcriptomic profile will be assessed by microarray |
| Plasma metabolomics | Fasting a.m. sample, before lunch, and at 0.5, 2, and 4.5 hours post lunch | Plasma metabolomic profile will be assessed using GC/MS and LC/MS platforms. |
Countries
United States
Outcome results
None listed