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Protocol Details

Study of the Phenotype of Overweight and Obese Adults

This study is currently recruiting participants.

Summary | Eligibility | Citations | Contacts




Sponsoring Institute

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

Recruitment Detail

Type: Participants currently recruited/enrolled
Gender: Male & Female
Min Age: 18 Years
Max Age: 100 Years

Referral Letter Required


Population Exclusion(s)



Energy Expenditure;
Body Composition;
Natural History

Recruitment Keyword(s)

Body Composition;
Morbid Obesity;
Healthy Volunteer


Healthy Volunteers

Investigational Drug(s)


Investigational Device(s)




Supporting Site

National Institute of Diabetes and Digestive and Kidney Diseases

This study will describe the phenotype (physical and behavioral traits) of overweight and obese people. It will characterize the hormones, metabolism, food preferences, fitness and physical activity levels, sleep patterns and thought processes in people with and without weight problems. Genetic material will be collected for studies of the internal codes that influence body weight.

People over 18 years of age from all weight categories (lean, overweight, obese) who are reasonably healthy may be eligible for this study. Participants undergo the following tests and procedures:

-Physical exam, electrocardiogram, blood and urine tests, instructions for recording food intake for 7 days

-Metabolic studies for menstruating women.

-Resting metabolic rate to study how many calories the body burns at rest.

-Mixed meal test to measure hormones such as insulin that regulate blood sugar.

-Glucose tolerance test to determine how sensitive the body is to insulin.

-24-hour energy expenditure to measure the amount of oxygen breathed in and the amount of carbon dioxide breathed out.

-Repeat 24-hour energy expenditure.

-Diurnal blood sampling and temperature assessment to study the body s internal clock.

-Air-displacement plethysmography (Bod Pod) to measure body composition.

-Dual energy x-ray absortiometry (DEXA) to measure body fat and bone density.

-Repeat Bod Pod and DEXA.

-Anthropometric measurements and bioelectrical impedance to measure height, weight, and circumferences, skinfold thickness, fluid status and percentage body fat.

-Bromide dilution to measure the amount of water not in cells in the body.

-Doubly labeled water to measure the amount of calories burned in a 7-day period.

-24-hour diet reports.

-Endothelial reactivity to measure how the blood vessels stretch or dilate for assessing cardiovascular health.

-Treadmill or bicycle exercise capacity test.

-Physical activity monitor.

-Unicorder to detect any breathing difficulties that may interfere with sleep.

-Fat and muscle biopsy to look for variations in gene expression in fat tissue and muscle.

-Neurocognitive testing to check memory, decision-making, hand-eye coordination, and reasoning.

-Evaluation of mood problems and assess personality type.

-Evaluation to assess the quantity and quality of pain experienced.

-Taste testing to determine the response to bitter, salty, sweet and sour substances.

-Occupational therapy evaluation to explore the subject s adaptations, if any, for performing personal, social or professional activities; the subject s views on his or her weight, body size and shape, and strategies to control weight.

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Obese subjects:

1. Obese men and women over the age of 18 years;

2. BMI greater than 30;

Overweight subjects:

1. Overweight men and women over the age of 18 years;

2. BMI greater than 25 and less than 30

Control subjects (may be matched for age, sex and years of education):

1. Normal weight men and women over the age of 18 years;

2. BMI greater than 18.5 and less than 25


1. Patients with significant physical limitations that may preclude them from completing the majority of the tests in this study.

2. Current, unstable medical conditions including cardiac ischemia; severe respiratory insufficiency requiring oxygen therapy; hepatic or cardiac failure as assessed by history and physical exam;

3. Any psychiatric condition that would preclude participation in the study;

4. Patients unwilling or unable to give informed consent.

5. Pregnant women

Additional exclusion for lean control subjects:

1. Previous history of obesity as an adolescent or adult;

2. Current or past history of eating disorders such as anorexia nervosa or bulimia.

Exclusions for both cannabis users and controls:

1. Dependence on drugs other than nicotine, caffeine and cannabis, within the past 6 months

2. Any history of intravenous illegal drug use

3. Alcohol use of more than 5 drinks per day, on 3 or more days in a week; or more than 15 drinks per week

4. History of hepatitis B or C or current hepatitis A, B or C, or other liver disease associated with steatosis

5. HIV

6. History of diabetes (type 1 or type 2) or polycystic ovary disease or other conditions that may confound our study results

7. Professional or collegiate athletes or participation in more than 60 minutes per day of vigorous exercise

8. Use of prescribed or over the counter or herbal/alternative medications/ preparations with effects on glucose and lipid metabolism other than oral contraceptives

9. Pregnancy or lactation

10. Any condition or physical attribute which would interfere with MRI study e.g. claustrophobia, cochlear implant, metal fragments in the eye, certain types of tattoos or other metal implanted in the body

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Adams KF, Schatzkin A, Harris TB, Kipnis V, Mouw T, Ballard-Barbash R, Hollenbeck A, Leitzmann MF. Overweight, obesity, and mortality in a large prospective cohort of persons 50 to 71 years old. N Engl J Med. 2006 Aug 24;355(8):763-78.

Calle EE, Rodriguez C, Walker-Thurmond K, Thun MJ. Overweight, obesity, and mortality from cancer in a prospectively studied cohort of U.S. adults. N Engl J Med. 2003 Apr 24;348(17):1625-38.

Fontaine KR, Redden DT, Wang C, Westfall AO, Allison DB. Years of life lost due to obesity. JAMA. 2003 Jan 8;289(2):187-93.

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Principal Investigator

Referral Contact

For more information:

Ranganath Muniyappa, M.D.
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
NIHBC 10 - CRC BG RM 6-3952
(301) 451-7702

Antoinette C. Rabel, C.R.N.P.
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
NIHBC 10 - CRC BG RM 6-5760
(301) 451-8893

Office of Patient Recruitment
National Institutes of Health Clinical Center (CC)
Building 61, 10 Cloister Court
Bethesda, Maryland 20892
Toll Free: 1-800-411-1222
Local Phone: 301-451-4383
TTY: TTY Users Dial 7-1-1

Clinical Trials Number:


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