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Selective Reduction of Dietary Carbohydrate Versus Fat: Effects on Metabolism, Endocrine Physiology, Brain Activity and Reward Circuitry
This study is currently recruiting participants.
Summary | Eligibility | Citations | Contacts
Summary
Number |
09-DK-0081 |
Sponsoring Institute |
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) |
Recruitment Detail |
Type: Participants currently recruited/enrolled |
Referral Letter Required |
No |
Population Exclusion(s) |
Children |
Special Instructions |
Currently Not Provided |
Keywords |
Obesity; |
Recruitment Keyword(s) |
Obesity; |
Condition(s) |
Obesity |
Investigational Drug(s) |
(f-18) fallypride |
Investigational Device(s) |
None |
Intervention(s) |
None |
Supporting Site |
|
- Popular weight loss strategies often involve reducing an individual's consumption of carbohydrates or fat. However, no controlled study has been carried out to evaluate the effects of reducing carbohydrate versus fat consumption while keeping the other nutrients at standard levels to maintain an individual's weight. Researchers are interested in investigating how different restrictions of carbohydrates or fats affect the many processes involved in weight loss, including brain activity and blood and brain chemical composition.
Objectives:
- To determine the comparative effects of two controlled fat- or carbohydrate-restricted diets and an outpatient weight loss program on blood and brain chemical composition, weight loss (fat and lean body mass), and regional brain activity in lean and obese individuals.
Eligibility:
- Healthy individuals between 18 and 45 years of age who are either lean (body mass index between 18.5 kg/m(2) and 25 kg/m(2)) or obese (body mass index above 30.0 kg/m(2), weight less than 350 pounds) and are right-handed.
Design:
- For obese participants, this study consists of four phases: an initial 2-day screening visit followed by two separate in-patient visits and one set of 12-week outpatient visits. For lean participants, this study consists of a scanning visit and a 2-day screening visit that will require an overnight stay.
- Lean participants
- Participants will be screened with a medical history, physical examination, blood and urine tests, and weight maintenance observations (food diaries and physical activity monitors).
- For the scanning visit, participants will receive balanced meals from the National Institutes of Health to consume for 2 days before the visit. During the scanning visit, participants will continue to eat the weight maintenance diet, complete questionnaires, and have a series of imaging studies (including positron emission tomography and magnetic resonance imaging tests) to evaluate brain response to food and other stimuli.
- Obese participants
- Participants will be screened with a medical history, physical examination, blood and urine tests, and weight maintenance observations (food diaries and physical activity monitors).
- During the first inpatient visit, obese participants will eat a weight-maintenance diet for 5 days to establish baseline measurements. Following the baseline diet, participants will then be switched to either a reduced-fat or a reduced-carbohydrate diet for the next 6 days. After the controlled diet, participants will have 3 days where they will be permitted to select food as desired from a computerized vending machine system. Participants will have frequent blood and other tests throughout this visit.
- After a 10-week washout period, participants will return for a second inpatient visit in which they will have the other (reduced-fat or reduced-carbohydrate) diet, with the same tests and procedures as before.
- After the second in-patient visit, participants will be assigned to a 12-week outpatient weight loss program with the goal of achieving at least 5% weight loss. During this program, participants will continue to have blood tests and imaging studies to evaluate the effects of weight loss on metabolism, brain reward circuitry, and regional brain activity.
- Participants who are available for long-term followup will have yearly visits for the next 5 years following the weight loss intervention.
Eligibility
INCLUSION CRITERIA:
- Age 18-45 years, male or female
- Body mass less than 350 lbs. (max. weight dictated by table limit for fMRI scanner) when acquisition of large bore fMRI is complete, max. wt. limit will increase to 400 lbs.
- Weight stable (less than plus or minus 5 kg over past 6 months)
- Body mass index greater than or equal to 30.0 kg/m(2)
- Premenopausal (women only)
- Healthy, as determined by medical history and laboratory tests
- Able to complete daily bouts of walking at a moderate rate
- Written informed consent
EXLCUSION CRITERIA:
- Body mass greater than 350 lbs. (max. weight dictated by table limit for fMRI scanner) when acquisition of large bore fMRI is complete, max. wt. limit will increase to 400 lbs.
- BMI less than 30.0 kg/m(2)
- Evidence of metabolic or cardiovascular disease, or disease that may influence metabolism (e.g. cancer, diabetes, thyroid disease)
- Taking any prescription medication (except birth control) or other drug that may influence metabolism (e.g. diet/weight-loss medication)
- Hematocrit less than 34% (women only)
- Hematocrit less than 40% (men only)
- Pregnancy, lactation (women only)
- Allergy to lidocaine or ethanol
- Participating in a regular exercise program (greater than 2h/week of vigorous activity)
- Caffeine consumption greater than 150 mg/day (will be clamped at baseline intake during study)
- Regular use of alcohol (greater than 2 drinks per day), tobacco (smoking or chewing), amphetamines, cocaine, heroin, or marijuana over past 6 months
- Past or present history of eating disorder (including binge eating) or psychiatric disease
- Volunteers with strict dietary concerns (e.g. vegetarian or kosher diet, multiple food allergies)
- Are claustrophobic to a degree that they would feel uncomfortable in the MRI machine.
- Having any metal in their body (for example, pacemakers, metallic prostheses such as cochlear implants or heart valves, shrapnel fragments, etc.).
- Left-handedness
- Non-native English speakers
- Volunteers unwilling or unable to give informed consent
Control Subjects
INCLUSION CRITERIA:
- Age 18-45 years, male or female
- 18.5 kg/m(2) less than BMI less than 25.0 kg/m(2)
- Weight stable (less than plus or minus 5 kg over past 6 months)
- Premenopausal (women only)
- Healthy, as determined by medical history and laboratory tests
- Written informed consent
EXCLUSION CRITERIA:
- BMI less than 18.5 or greater than 25.0 kg/m(2)
- Evidence of metabolic or cardiovascular disease, or disease that may influence metabolism (e.g. cancer or diabetes)
- Taking any prescription medication (except birth control) or other drug that may influence metabolism (e.g. diet/weight-loss medication)
- Hyperlipidemia (fasting plasma triglyceride concentration greater than 150 mg/dl)
- Hematocrit less than 34% (women only)
- Hematocrit less than 40% (men only)
- Pregnancy, lactation (women only)
- Participating in a regular exercise program (greater than 2h/week of vigorous activity)
- Caffeine consumption greater than 150 mg/day
- Regular use of alcohol (greater than 2 drinks per day), tobacco (smoking or chewing), amphetamines, cocaine, heroin, or marijuana over the past 6 months
- Past or present history of eating disorder (including binge eating) or psychiatric disease
- Volunteers with strict dietary concerns (e.g vegetarian or kosher diet, multiple food allergies)
- Are claustrophobic to a degree that they would feel uncomfortable in the MRI machine.
- Having any metal in their body (for example, pacemakers, metallic prostheses such as cochlear implants or heart valves, shrapnel fragments, etc.).
- Left-handedness
- Non-native English speakers
- Volunteers unwilling or unable to give informed consent
Citations:
Contacts:
Principal Investigator |
Referral Contact |
For more information: |
| Kevin Hall, Ph.D. National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) National Institutes of Health Building 12A Room 4007 12 South Drive Bethesda, Maryland 20892 (301) 402-8248 kevinh@helix.nih.gov |
Kevin Hall, Ph.D. National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) National Institutes of Health Building 12A Room 4007 12 South Drive Bethesda, Maryland 20892 (301) 402-8248 kevinh@helix.nih.gov |
Patient Recruitment and Public Liaison Office Building 61 10 Cloister Court Bethesda, Maryland 20892-4754 Toll Free: 1-800-411-1222 TTY: 301-594-9774 (local),1-866-411-1010 (toll free) Fax: 301-480-9793 prpl@mail.cc.nih.gov |
Clinical Trials Number:
NCT00846040
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