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Reduced Carbohydrate Versus Fat in Obese Subjects

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ClinicalTrials.gov Identifier: NCT00846040
Recruitment Status : Completed
First Posted : February 18, 2009
Results First Posted : March 24, 2021
Last Update Posted : April 15, 2021
Sponsor:
Information provided by (Responsible Party):
National Institutes of Health Clinical Center (CC) ( National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) )

Brief Summary:
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.

Condition or disease Intervention/treatment Phase
Obesity Other: Reduced fat diet Other: Reduced carbohydrate diet Drug: Drug: f-18 fallypride Device: fMRI Device: PET Phase 2

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Study Type : Interventional  (Clinical Trial)
Actual Enrollment : 43 participants
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: None (Open Label)
Primary Purpose: Treatment
Official Title: Selective Reduction of Dietary Carbohydrate Versus Fat: Effects on Metabolism, Endocrine Physiology, Brain Activity and Reward Circuitry
Study Start Date : February 13, 2009
Actual Primary Completion Date : February 24, 2014
Actual Study Completion Date : October 20, 2014

Arm Intervention/treatment
Experimental: Obese RF then RC
Obese adult volunteers (BMI above 30 kg/m2) randomized to receive an 85% reduction of baseline dietary fat (RF) for 2 weeks. After a washout period of 2 weeks, they then received a 60% reduction of baseline dietary carbohydrate (RC) for 2 weeks
Other: Reduced fat diet
RF (selective reduction of 85% of baseline fat calories per day)

Other: Reduced carbohydrate diet
RC (selective reduction of 60% of baseline carbohydrate calories per day)

Drug: Drug: f-18 fallypride
Dopamine D2 receptor availability is measured by positron emission tomography (PET) using the positron emitting compound [18F] fallypride which binds competitively with dopamine to the D2 receptor.

Device: fMRI
Functional MRI (fMRI) will be used to measure the effects of diet and weight loss on regional brain activity
Other Name: Functional MRI

Device: PET
Positron emission tomography (PET) will be used to assess whether To assess whether brain activity and reward pathways are altered
Other Name: Positron emission tomography

Experimental: Obese RC then RF
Obese adult volunteers (BMI above 30 kg/m2) randomized to receive a 60% reduction of baseline dietary carbohydrate (RC) for 2 weeks. After a washout period of 2 weeks, they then received an 85% reduction of baseline dietary fat (RF) for 2 weeks.
Other: Reduced fat diet
RF (selective reduction of 85% of baseline fat calories per day)

Other: Reduced carbohydrate diet
RC (selective reduction of 60% of baseline carbohydrate calories per day)

Drug: Drug: f-18 fallypride
Dopamine D2 receptor availability is measured by positron emission tomography (PET) using the positron emitting compound [18F] fallypride which binds competitively with dopamine to the D2 receptor.

Device: fMRI
Functional MRI (fMRI) will be used to measure the effects of diet and weight loss on regional brain activity
Other Name: Functional MRI

Device: PET
Positron emission tomography (PET) will be used to assess whether To assess whether brain activity and reward pathways are altered
Other Name: Positron emission tomography

Active Comparator: Lean Control
Lean adult volunteers (BMI below 30kg/m2) placed on a weight-maintenance diet using a standard diet composition of 50% carbohydrate, 35% fat, and 15% protein on an out-patient basis
Drug: Drug: f-18 fallypride
Dopamine D2 receptor availability is measured by positron emission tomography (PET) using the positron emitting compound [18F] fallypride which binds competitively with dopamine to the D2 receptor.

Device: fMRI
Functional MRI (fMRI) will be used to measure the effects of diet and weight loss on regional brain activity
Other Name: Functional MRI

Device: PET
Positron emission tomography (PET) will be used to assess whether To assess whether brain activity and reward pathways are altered
Other Name: Positron emission tomography




Primary Outcome Measures :
  1. Change in Respiratory Quotient (RQ) [ Time Frame: Baseline and day 14 ]
    Respiratory quotient was calculated as the ratio of carbon dioxide production to oxygen consumption as measured in a metabolic chamber for at least 23 continuous hours on days 2 and 5 of the baseline diet and days 1, 4, and 6 of the reduced-energy diets.


Secondary Outcome Measures :
  1. Change in 24 Hour Energy Expenditure [ Time Frame: Baseline and 14 days ]
    24 hour energy expenditure was measured in a respiratory chamber.

  2. Change in Cumulative Fat Imbalance [ Time Frame: Baseline and 14 days ]
    Measured as the difference between dietary fat intake and fat oxidation by the body as measured in the respiratory chamber

  3. Caudate Dopamine D2-like Receptor Binding Potential (D2BP) [ Time Frame: Day 2 of in-patient admission ]
    The time-activity curves for [18F]fallypride tracer concentration in the ROIs were measured by PET and kinetic parameters were fit to a four compartment mathematical model (with the cerebellum used as the reference tissue). D2BP was expressed as the dimensionless ratio of rate constants quantifying binding and unbinding of tracer in the regions of interest.

  4. Putamen Dopamine D2-like Receptor Binding Potential (D2BP) [ Time Frame: Day 2 of in-patient admission ]
    The time-activity curves for [18F]fallypride tracer concentration in the ROIs were measured by PET and kinetic parameters were fit to a four compartment mathematical model (with the cerebellum used as the reference tissue). D2BP was expressed as the dimensionless ratio of rate constants quantifying binding and unbinding of tracer in the regions of interest.

  5. Accumbens Dopamine D2-like Receptor Binding Potential (D2BP) [ Time Frame: Day 2 of in-patient admission ]
    The time-activity curves for [18F]fallypride tracer concentration in the ROIs were measured by PET and kinetic parameters were fit to a four compartment mathematical model (with the cerebellum used as the reference tissue). D2BP was expressed as the dimensionless ratio of rate constants quantifying binding and unbinding of tracer in the regions of interest.



Information from the National Library of Medicine

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Ages Eligible for Study:   18 Years to 45 Years   (Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No
Criteria
  • INCLUSION CRITERIA:
  • Age 18-45 years, male or female
  • Body mass less than 350 lbs. (max. weight dictated by table limit for functional magnetic resonance imaging (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

EXCLUSION 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

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT00846040


Locations
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United States, Maryland
National Institutes of Health Clinical Center, 9000 Rockville Pike
Bethesda, Maryland, United States, 20892
Sponsors and Collaborators
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Investigators
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Principal Investigator: Kevin Hall, Ph.D. National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
  Study Documents (Full-Text)

Documents provided by National Institutes of Health Clinical Center (CC) ( National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) ):
Additional Information:
Publications of Results:
Other Publications:
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Responsible Party: National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
ClinicalTrials.gov Identifier: NCT00846040    
Other Study ID Numbers: 090081
09-DK-0081 ( Other Identifier: NIDDK/NIH )
First Posted: February 18, 2009    Key Record Dates
Results First Posted: March 24, 2021
Last Update Posted: April 15, 2021
Last Verified: January 22, 2020

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Studies a U.S. FDA-regulated Drug Product: Yes
Studies a U.S. FDA-regulated Device Product: Yes
Keywords provided by National Institutes of Health Clinical Center (CC) ( National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) ):
Obesity
Weight Loss
Carbohydrate
Fat
Macronutrient Balance
Healthy Volunteer
Additional relevant MeSH terms:
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Obesity
Overnutrition
Nutrition Disorders
Overweight
Body Weight
Fallypride
Dopamine D2 Receptor Antagonists
Dopamine Antagonists
Dopamine Agents
Neurotransmitter Agents
Molecular Mechanisms of Pharmacological Action
Physiological Effects of Drugs