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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) )

Study Type Interventional
Study Design Allocation: Randomized;   Intervention Model: Crossover Assignment;   Masking: None (Open Label);   Primary Purpose: Treatment
Condition Obesity
Interventions Other: Reduced fat diet
Other: Reduced carbohydrate diet
Drug: Drug: f-18 fallypride
Device: fMRI
Device: PET
Enrollment 43
Recruitment Details 71 participants were screened and 43 were enrolled.
Pre-assignment Details  
Arm/Group Title Obese RF Then RC Obese RC Then RF Lean Control
Hide Arm/Group Description Obese adult volunteers (BMI above 30 kg/m2) randomized to receive an 85% reduction of baseline dietary fat for 2 weeks, then a 60% reduction of baseline dietary carbohydrate for 2 weeks. Each admission starts with a 5 day baseline period before the randomized diet. Obese adult volunteers (BMI above 30 kg/m2) randomized to receive a 60% reduction of baseline dietary carbohydrate for 2 weeks, then an 85% reduction of baseline dietary fat for 2 weeks. Each admission starts with a 5 day baseline period before the randomized diet. 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 for 2 days on an out-patient basis followed by an admission to the metabolic unit for 3 days.
Period Title: Baseline: Days 1-5
Started 10 10 23
Completed 9 10 23
Not Completed 1 0 0
Reason Not Completed
Withdrawal by Subject             1             0             0
Period Title: First Treatment Period: Days 6-14
Started 9 10 0 [1]
Completed 9 10 0
Not Completed 0 0 0
[1]
This group participated in only the baseline period
Period Title: Washout: 2 Weeks to 10 Weeks
Started 9 10 0
Completed 9 8 0
Not Completed 0 2 0
Reason Not Completed
Withdrawal by Subject             0             2             0
Period Title: Second Treatment: After Washout, 14 Day
Started 9 8 0
Completed 9 8 0
Not Completed 0 0 0
Arm/Group Title Obese RF Then RC Obese RC Then RF Lean Control Total
Hide Arm/Group Description Obese adult volunteers (BMI above 30 kg/m2) randomized to receive an 85% reduction of baseline dietary fat for 2 weeks, then a 60% reduction of baseline dietary carbohydrate for 2 weeks Obese adult volunteers (BMI above 30 kg/m2) randomized to receive a 60% reduction of baseline dietary carbohydrate for 2 weeks, then an 85% reduction of baseline dietary fat for 2 weeks. 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 Total of all reporting groups
Overall Number of Baseline Participants 10 10 23 43
Hide Baseline Analysis Population Description
[Not Specified]
Age, Continuous  
Mean (Standard Deviation)
Unit of measure:  Years
Number Analyzed 10 participants 10 participants 23 participants 43 participants
34.1  (6.9) 35.6  (8.1) 28  (6.2) 31.2  (7.5)
Sex: Female, Male  
Measure Type: Count of Participants
Unit of measure:  Participants
Number Analyzed 10 participants 10 participants 23 participants 43 participants
Female
6
  60.0%
4
  40.0%
11
  47.8%
21
  48.8%
Male
4
  40.0%
6
  60.0%
12
  52.2%
22
  51.2%
Ethnicity (NIH/OMB)  
Measure Type: Count of Participants
Unit of measure:  Participants
Number Analyzed 10 participants 10 participants 23 participants 43 participants
Hispanic or Latino
0
   0.0%
1
  10.0%
0
   0.0%
1
   2.3%
Not Hispanic or Latino
9
  90.0%
9
  90.0%
23
 100.0%
41
  95.3%
Unknown or Not Reported
1
  10.0%
0
   0.0%
0
   0.0%
1
   2.3%
Race (NIH/OMB)  
Measure Type: Count of Participants
Unit of measure:  Participants
Number Analyzed 10 participants 10 participants 23 participants 43 participants
American Indian or Alaska Native
0
   0.0%
0
   0.0%
0
   0.0%
0
   0.0%
Asian
0
   0.0%
1
  10.0%
2
   8.7%
3
   7.0%
Native Hawaiian or Other Pacific Islander
0
   0.0%
0
   0.0%
0
   0.0%
0
   0.0%
Black or African American
6
  60.0%
8
  80.0%
12
  52.2%
26
  60.5%
White
3
  30.0%
1
  10.0%
9
  39.1%
13
  30.2%
More than one race
0
   0.0%
0
   0.0%
0
   0.0%
0
   0.0%
Unknown or Not Reported
1
  10.0%
0
   0.0%
0
   0.0%
1
   2.3%
1.Primary Outcome
Title Change in Respiratory Quotient (RQ)
Hide Description 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.
Time Frame Baseline and day 14
Hide Outcome Measure Data
Hide Analysis Population Description
[Not Specified]
Arm/Group Title RC Diet RF Diet
Hide Arm/Group Description:
Reduced carbohydrate diet
Reduced fat diet
Overall Number of Participants Analyzed 19 17
Mean (Standard Error)
Unit of Measure: ratio
-0.0552  (0.003) 0.00453  (0.003)
2.Secondary Outcome
Title Change in 24 Hour Energy Expenditure
Hide Description 24 hour energy expenditure was measured in a respiratory chamber.
Time Frame Baseline and 14 days
Hide Outcome Measure Data
Hide Analysis Population Description
[Not Specified]
Arm/Group Title RC Diet RF Diet
Hide Arm/Group Description:
Reduced carbohydrate diet
Reduced fat diet
Overall Number of Participants Analyzed 19 17
Mean (Standard Error)
Unit of Measure: kcal/day
-97.7  (23) -49.6  (24)
3.Secondary Outcome
Title Change in Cumulative Fat Imbalance
Hide Description Measured as the difference between dietary fat intake and fat oxidation by the body as measured in the respiratory chamber
Time Frame Baseline and 14 days
Hide Outcome Measure Data
Hide Analysis Population Description
[Not Specified]
Arm/Group Title RC Diet RF Diet
Hide Arm/Group Description:
Reduced carbohydrate diet
Reduced fat diet
Overall Number of Participants Analyzed 19 17
Mean (Standard Error)
Unit of Measure: grams
-245  (21) -463  (37)
4.Secondary Outcome
Title Caudate Dopamine D2-like Receptor Binding Potential (D2BP)
Hide Description 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.
Time Frame Day 2 of in-patient admission
Hide Outcome Measure Data
Hide Analysis Population Description
[Not Specified]
Arm/Group Title Obese Lean Control
Hide Arm/Group Description:
Obese adult volunteers (BMI above 30 kg/m2)
Lean adult volunteers (BMI below 30kg/m2)
Overall Number of Participants Analyzed 20 23
Mean (95% Confidence Interval)
Unit of Measure: ratio
28.2
(26.48 to 29.86)
24.9
(22.95 to 26.92)
5.Secondary Outcome
Title Putamen Dopamine D2-like Receptor Binding Potential (D2BP)
Hide Description 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.
Time Frame Day 2 of in-patient admission
Hide Outcome Measure Data
Hide Analysis Population Description
[Not Specified]
Arm/Group Title Obese Lean Control
Hide Arm/Group Description:
Obese adult volunteers (BMI above 30 kg/m2)
Lean adult volunteers (BMI below 30kg/m2)
Overall Number of Participants Analyzed 20 23
Mean (95% Confidence Interval)
Unit of Measure: ratio
30.7
(28.61 to 32.7)
27
(25.14 to 28.93)
6.Secondary Outcome
Title Accumbens Dopamine D2-like Receptor Binding Potential (D2BP)
Hide Description 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.
Time Frame Day 2 of in-patient admission
Hide Outcome Measure Data
Hide Analysis Population Description
[Not Specified]
Arm/Group Title Obese Lean Control
Hide Arm/Group Description:
Obese adult volunteers (BMI above 30 kg/m2)
Lean adult volunteers (BMI below 30kg/m2)
Overall Number of Participants Analyzed 20 23
Mean (95% Confidence Interval)
Unit of Measure: ratio
18.3
(16.6 to 19.94)
16.7
(14.16 to 19.29)
Time Frame Up to 12 weeks after the second in-patient visit
Adverse Event Reporting Description [Not Specified]
 
Arm/Group Title Obese Reduced Carbohydrate Obese Reduced Fat Lean Control
Hide Arm/Group Description Reduced carbohydrate diet (selective reduction of 60% of baseline carbohydrate calories per day) Reduced fat diet (selective reduction of 85% of baseline fat calories per day) 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
All-Cause Mortality
Obese Reduced Carbohydrate Obese Reduced Fat Lean Control
Affected / at Risk (%) Affected / at Risk (%) Affected / at Risk (%)
Total   0/19 (0.00%)   0/17 (0.00%)   0/23 (0.00%) 
Hide Serious Adverse Events
Obese Reduced Carbohydrate Obese Reduced Fat Lean Control
Affected / at Risk (%) Affected / at Risk (%) Affected / at Risk (%)
Total   0/19 (0.00%)   0/17 (0.00%)   0/23 (0.00%) 
Hide Other (Not Including Serious) Adverse Events
Frequency Threshold for Reporting Other Adverse Events 0%
Obese Reduced Carbohydrate Obese Reduced Fat Lean Control
Affected / at Risk (%) Affected / at Risk (%) Affected / at Risk (%)
Total   0/19 (0.00%)   0/17 (0.00%)   0/23 (0.00%) 
Certain Agreements
All Principal Investigators ARE employed by the organization sponsoring the study.
Results Point of Contact
Layout table for Results Point of Contact information
Name/Title: Kevin Hall, PhD
Organization: National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Phone: 3014028248
EMail: kevinh@niddk.nih.gov
Layout table for additonal information
Responsible Party: National Institutes of Health Clinical Center (CC) ( 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 Submitted: February 14, 2009
First Posted: February 18, 2009
Results First Submitted: October 7, 2020
Results First Posted: March 24, 2021
Last Update Posted: April 15, 2021