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View Clinical Trial (Medical Research Study)
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Diet-Induced-Obesity Resistant Phenotypes in Humans - NCT00999154-20892 (Clinical Trial 378884)
Permalink: http://www.ClinicalConnection.com/exp/ExpandedPatientViewStudy378884.aspx
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| City: |
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Bethesda |
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State:
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MD |
| Zip Code: |
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20892 |
| Conditions: |
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Healthy Volunteers |
| Purpose: |
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Background:
- Obesity is the result of many factors, including genetics and lifestyle, such as
over-eating high-calorie foods and not being physically active. Obesity affects
approximately one third of adults in the United States. Researchers often study individuals
who are already overweight and obese, but another approach is to examine people who stay
thin despite eating whatever they want and not exercising. Studying these thin individuals
will enhance understanding of why some people become obese and others do not, which may lead
to novel treatments for obesity.
Objective:
- To study the metabolism, body composition, body temperature, physical activity, and blood
chemistries of healthy lean adults before and after adding 1,000 extra Calories per day to
their normal diet.
Eligibility:
- Healthy adults, 30 to 50 years of age, who have never been overweight after adolescence,
who are currently weight-stable, sedentary, and eating without restrictions.
Design:
- The entire study will take about 9 weeks and will include the following outpatient and
inpatient visits:
- Outpatient screening visit and monitoring: Physical examination and blood test at
screening; then, one week of physical activity monitoring (e.g., with a pedometer-like
device called an accelerometer) and completing a food diary.
- Baseline inpatient visit (5 days): Volunteers will eat a normal diet to maintain body
weight. Energy expenditure, body composition, physical fitness, activity level, and
eating behavior will be measured. Urine and blood samples will be taken. Volunteers may
go home for the weekend or stay at the metabolic clinical research unit (MCRU).
- Inpatient feeding week 1 (5 days): Volunteers will eat a normal diet plus milkshakes
for added calories. All the same measurements during the baseline week visit will be
repeated.
- Outpatient feeding weeks 2-3: Volunteers will eat breakfast at the MCRU everyday for
the next 2 weeks and take prepared meals home with them (volunteers may also stay at
the MCRU for the 2 weeks if they prefer). Volunteers will drink a non-radioactive
(heavy) water called doubly labeled water to measure energy expenditure in their normal
living environment Daily urine samples will be collected.
- Inpatient feeding week 4 (5 days): Volunteers will continue eating a normal diet plus
milkshakes for added calories. This stay and measurement is identical to inpatient
feeding week 1.
- Volunteers will be cont...
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| Study summary: |
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While many obesity studies focus on the individuals who are already overweight and obese, a
complementary approach to understand such a common disease is to define the mechanisms which
allow some lean individuals to resist weight gain. The predominant cause of human obesity is
the inheritance of genes favoring fat storage and efficient energy utilization interacting
with an obesogenic environment, characterized by readily available, energy-dense food and
sedentary lifestyle. However, a persistent percentage (about 30%) of the US adult population
remains thin (BMI < 23 kg/M(2)). While some of these individuals maintain their weight by
vigilantly controlling their diet, exercising or taking medication(s), others may have the
ability to remain thin despite an excessive energy intake and without volitional exercise.
To identify these individuals and define their phenotypes will provide unique insights into
energy and body weight homeostasis, and may yield novel approaches for treating obesity.
In this natural history protocol, we will recruit and characterize a cohort of
constitutionally lean and healthy adult volunteers (age 30-50, BMI 18.5-23 kg/M(2)) who do
not have pathological or exogenous factors that are known to stimulate energy expenditure,
suppress food intake, or decrease absorption. We will recruit volunteers who are
weight-stable, sedentary, and non-restrictive eaters, characterize their free-living dietary
and physical activity energy expenditure using food records and portable accelerometers,
respectively. Using an inpatient controlled setting, we will carefully characterize the
details of their 24-hr energy metabolism, body composition, core and skin temperatures, and
blood chemistries while they are on a one-week metabolic diet adjusted to maintain his/her
body weight (baseline) vs. another week of higher energy intake level (1000 extra kcal per
day above their baseline). Overfeeding will continue for two more weeks in the outpatient
setting with all meals provided by our metabolic kitchen, followed by the fourth week of
overfeeding and repeated measurements back in the inpatient setting. We hypothesize that
spontaneous changes in energy expenditure and/or calorie intake may differ between
individuals, and such difference may explain the ability for some to resist body gain. The
accruals of humans with obesity-resistant phenotypes will significantly enhance our
understanding of the mechanisms of energy homeostasis and identify potential novel
regulators for controlling obesity. |
| Criteria: |
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- INCLUSION CRITERIA:
1. Healthy normal men and women between 30-50 years of age;
2. BMI between 18.5 and 23.0 kg/M(2);
3. Self-reported as having had trouble gaining weight, who doing little or no
exercise, self-described or by friends or family members as an overeater, and
who have never tried to lose weight.
EXCLUSION CRITERIA:
1. A self-reported history of overweight after the age of 18, other than during
pregnancy for women;
2. Recent weight changes > 2% of current body weight in the last 6 months;
3. Current or past history of eating disorders such as binge eating, anorexia nervosa,
or bulimia, by psychological evaluations;
4. Current or past history of intentional weight loss by self-report, other than
postpartum weight loss;
5. High physically demanding occupations or volitional exercise > 20 total minutes/day
of moderate intensity or higher (as measured by sweating), > 2 days/week, by
self-report;
6. Significant dietary limitations (multiple food allergies/intolerances, vegan diet,
etc.) that may affect absorption and body weight, or special dietary requirements
that are difficult to accommodate with by study diets;
7. Significant physical limitations that may preclude completing the majority of the
tests in this study;
8. Current pregnancy, recent pregnancy (< 3 years), current/recent breast feeding (< 1
year), or perimenopausal status. During the study, women may be asked to use birth
control and will undergo repeated pregnancy testing. Subjects who refuse these tests
will be excluded;
9. Current or past medical conditions that are known to affect energy metabolism and
body weight regulations, including HIV/AIDS, cancer, cardiac ischemia, dyslipidemia,
thyroid and parathyroid disorders, hypo- or hypertension, diabetes (type 1 or type 2)
or impaired glucose tolerance, congenital or acquired lipodystrophy, hepatic, renal,
neuromuscular, celiac disease and other malabsorptive conditions, known genetic
disorders that alter lipid metabolism, or cardiac failure as assessed by history and
physical exam;
10. Any psychiatric condition (including psychosis) or personality disorder as judged by
the PI or Co-PI that would impede participation in the study;
11. Smoking (currently or within the past year), excessive caffeine (> 500 mg/day) and/or
alcohol intake (> 2 drinks/day for men, > 1 drink/day for women), as assessed by
self reports;
12. Any use of medications or nutritional supplements known to increase EE, depress food
intake, or affect absorption;
13. Unwilling or unable to give informed consent;
14. Any other clinical or sub-clinical conditions not mentioned above that are considered
by the investigators as significant exclusions for the study. |
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| Study is available at: |
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National Institutes of Health Clinical Center, 9000 Rockville Pike
Bethesda, MD 20892
United States
Primary Contact:
Patient Recruitment and Public Liaison Office
Email: prpl@mail.cc.nih.gov
Phone: (800) 411-1222 |
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If you are interested in this clinical trial please use the contact information above. If you would like to get additional information about this clinical trial please visit ClinicalTrials.gov.
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| Data Source: |
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ClinicalTrials.gov |
| Date Processed: |
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November 17, 2009 |
Modifications to
this listing: |
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Only selected fields are shown, please use the link
above to view all information about this clinical trial. |
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Clinical trials are medical research studies designed to test the safety and/or
effectiveness of new drugs, devices, or treatments in humans. These studies are
conducted worldwide for a range of conditions and illnesses. Learn more about
clinical research and participating in a study at
About Clinical Trials.
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