Water Deprivation Protocol

Completed · Not applicable

Conditions studied: Obesity

In brief

Background: \- One area in which obese and lean individuals may be different is how their bodies handle water balance and thirst. Studies done in animals suggest that individuals with greater body fat may tolerate periods without water better than lean animals. Other research has found a link between the ability to tolerate periods without water and increased body weight. Researchers are interested in studying whether the ability to tolerate periods without water and ability to feel thirst might differ in lean versus obese individuals. Objectives: \- To evaluate the effects of water deprivation and feelings of thirst in lean and obese individuals. Eligibility: \- Healthy individuals at least 18 years of age who are either lean (body mass index less than 26 kg/m(2)) or obese (body mass index at least 35 kg/m(2)). Design: * Participants will be screened with a medical history, physical examination, and blood and urine tests. * Participants will spend the entire study (13 days) as inpatients at the National Institutes of Health Clinical Center. * Participants will have the following tests and procedures: * Body composition assessment (using low-level x-rays) to determine the percentage of fat tissue in the body. * Oral glucose tolerance test (similar to that often used to diagnose diabetes). Individuals who are suspected to have diabetes will not be allowed to continue with the study. * High salt infusion test, in which an infusion of saline (salt water) will be given for 2 hours and participants will respond to questions about how hungry and thirsty they feel during the procedure. * Water deprivation test, in which participants will go for 24 hours without water or food and respond to questions about how hungry and thirsty they feel. * 24-hour stay in a metabolic chamber to determine how many calories participants burn in a day. * A series of questionnaires about participants' eating habits, feelings about food, and personal feelings, as well as computer-based tests involving the performance of various tasks. * Measurement of free-living energy using doubly-labeled water, in which participants will drink a sample of water with extra-heavy atoms of hydrogen and oxygen to evaluate the amount of water in the body. * 24-hour urine collection. * Frequent blood samples, urine collection, and fat tissue biopsies during the various study procedures. * After the end of the 13-day study, participants will return after 1 week for a final urine collection.

Key facts

Study ID

NCT01224704

Run by

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

People needed

75

Starts

2010-10-19

Expected to finish

2019-03-28

Last updated by the study team

2026-07-02

Who can join

Age: 18 and older, up to 50. Sex: male. Healthy volunteers: not accepted.

You may not qualify if…

• History or Clinical Manifestation of:
• Currently smoking
• Any medications
• Weight <50kg (as the blood withdrawal limit would be exceeded)
• Hemoglobin concentration < 12mg/dl on screening labs
• Type 1 or type 2 diabetes (according to World Health Organization diagnostic criteria (59))
• Endocrine disorders (Cushing's disease, pituitary diseases, hypo- or hyperthyroidism, diabetes insipidus, SIADH)
• Hypertension as diagnosed and treated by an outside physician or by sitting blood pressure measurement, using an appropriate cuff, >140/90 mmHg on two or more occasions
• Fasting triglyceride concentrations >= 500 mg/dl
• Cardiovascular disease, including coronary heart disease, heart failure, arrhythmias and peripheral arterial disease
• Liver disease, including cirrhosis, active hepatitis B or C and AST or ALT >= 3x normal
• Renal disease, as defined by serum creatinine concentrations >= 1.5 mg/dl and / or proteinuria >300 mg/day (200 (micro)g/min)
• Central nervous system disease, including previous history of cerebrovascular accidents, dementia, and neurodegenerative disorders
• Cancer requiring treatment in the past five years, except for non-melanoma skin cancers or cancers that have been clearly cured or, in the opinion of the investigator, carry an excellent prognosis
• Infectious diseases such as active tuberculosis, HIV (by self report), chronic coccidioidomycoses or other chronic infections
• Alcohol and/or current use of drugs (more than 2 drinks per day and regular use of drugs such as amphetamines, cocaine, heroin, or marijuana)
• Psychiatric conditions or behaviors that would be incompatible with safe and successful participation in this study, including claustrophobia and eating disorders such as anorexia or bulimia nervosa
• All subjects will be fully informed of the aim, nature, and risks of the study prior to giving written informed consent. Subjects will also be specifically advised that the results of testing for drug usage will be filed in the medical record and would, therefore, be available as part of this record.

Where it is running

• NIDDK, Phoenix — Phoenix, Arizona, United States

Full record on ClinicalTrials.gov

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