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Trial Outcomes & Findings for Reduced Carbohydrate Versus Fat in Obese Subjects (NCT NCT00846040)

NCT ID: NCT00846040

Last Updated: 2021-04-15

Results Overview

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.

Recruitment status

COMPLETED

Study phase

PHASE2

Target enrollment

43 participants

Primary outcome timeframe

Baseline and day 14

Results posted on

2021-04-15

Participant Flow

71 participants were screened and 43 were enrolled.

Participant milestones

Participant milestones
Measure
Obese RF Then RC
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 RC Then RF
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 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 for 2 days on an out-patient basis followed by an admission to the metabolic unit for 3 days.
Baseline: Days 1-5
STARTED
10
10
23
Baseline: Days 1-5
COMPLETED
9
10
23
Baseline: Days 1-5
NOT COMPLETED
1
0
0
First Treatment Period: Days 6-14
STARTED
9
10
0
First Treatment Period: Days 6-14
COMPLETED
9
10
0
First Treatment Period: Days 6-14
NOT COMPLETED
0
0
0
Washout: 2 Weeks to 10 Weeks
STARTED
9
10
0
Washout: 2 Weeks to 10 Weeks
COMPLETED
9
8
0
Washout: 2 Weeks to 10 Weeks
NOT COMPLETED
0
2
0
Second Treatment: After Washout, 14 Day
STARTED
9
8
0
Second Treatment: After Washout, 14 Day
COMPLETED
9
8
0
Second Treatment: After Washout, 14 Day
NOT COMPLETED
0
0
0

Reasons for withdrawal

Reasons for withdrawal
Measure
Obese RF Then RC
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 RC Then RF
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 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 for 2 days on an out-patient basis followed by an admission to the metabolic unit for 3 days.
Baseline: Days 1-5
Withdrawal by Subject
1
0
0
Washout: 2 Weeks to 10 Weeks
Withdrawal by Subject
0
2
0

Baseline Characteristics

Reduced Carbohydrate Versus Fat in Obese Subjects

Baseline characteristics by cohort

Baseline characteristics by cohort
Measure
Obese RF Then RC
n=10 Participants
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 RC Then RF
n=10 Participants
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 Control
n=23 Participants
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
n=43 Participants
Total of all reporting groups
Age, Continuous
34.1 years
STANDARD_DEVIATION 6.9 • n=5 Participants
35.6 years
STANDARD_DEVIATION 8.1 • n=7 Participants
28 years
STANDARD_DEVIATION 6.2 • n=5 Participants
31.2 years
STANDARD_DEVIATION 7.5 • n=4 Participants
Sex: Female, Male
Female
6 Participants
n=5 Participants
4 Participants
n=7 Participants
11 Participants
n=5 Participants
21 Participants
n=4 Participants
Sex: Female, Male
Male
4 Participants
n=5 Participants
6 Participants
n=7 Participants
12 Participants
n=5 Participants
22 Participants
n=4 Participants
Ethnicity (NIH/OMB)
Hispanic or Latino
0 Participants
n=5 Participants
1 Participants
n=7 Participants
0 Participants
n=5 Participants
1 Participants
n=4 Participants
Ethnicity (NIH/OMB)
Not Hispanic or Latino
9 Participants
n=5 Participants
9 Participants
n=7 Participants
23 Participants
n=5 Participants
41 Participants
n=4 Participants
Ethnicity (NIH/OMB)
Unknown or Not Reported
1 Participants
n=5 Participants
0 Participants
n=7 Participants
0 Participants
n=5 Participants
1 Participants
n=4 Participants
Race (NIH/OMB)
American Indian or Alaska Native
0 Participants
n=5 Participants
0 Participants
n=7 Participants
0 Participants
n=5 Participants
0 Participants
n=4 Participants
Race (NIH/OMB)
Asian
0 Participants
n=5 Participants
1 Participants
n=7 Participants
2 Participants
n=5 Participants
3 Participants
n=4 Participants
Race (NIH/OMB)
Native Hawaiian or Other Pacific Islander
0 Participants
n=5 Participants
0 Participants
n=7 Participants
0 Participants
n=5 Participants
0 Participants
n=4 Participants
Race (NIH/OMB)
Black or African American
6 Participants
n=5 Participants
8 Participants
n=7 Participants
12 Participants
n=5 Participants
26 Participants
n=4 Participants
Race (NIH/OMB)
White
3 Participants
n=5 Participants
1 Participants
n=7 Participants
9 Participants
n=5 Participants
13 Participants
n=4 Participants
Race (NIH/OMB)
More than one race
0 Participants
n=5 Participants
0 Participants
n=7 Participants
0 Participants
n=5 Participants
0 Participants
n=4 Participants
Race (NIH/OMB)
Unknown or Not Reported
1 Participants
n=5 Participants
0 Participants
n=7 Participants
0 Participants
n=5 Participants
1 Participants
n=4 Participants

PRIMARY outcome

Timeframe: 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.

Outcome measures

Outcome measures
Measure
RC Diet
n=19 Participants
Reduced carbohydrate diet
RF Diet
n=17 Participants
Reduced fat diet
Change in Respiratory Quotient (RQ)
-0.0552 ratio
Standard Error 0.003
0.00453 ratio
Standard Error 0.003

SECONDARY outcome

Timeframe: Baseline and 14 days

24 hour energy expenditure was measured in a respiratory chamber.

Outcome measures

Outcome measures
Measure
RC Diet
n=19 Participants
Reduced carbohydrate diet
RF Diet
n=17 Participants
Reduced fat diet
Change in 24 Hour Energy Expenditure
-97.7 kcal/day
Standard Error 23
-49.6 kcal/day
Standard Error 24

SECONDARY outcome

Timeframe: Baseline and 14 days

Measured as the difference between dietary fat intake and fat oxidation by the body as measured in the respiratory chamber

Outcome measures

Outcome measures
Measure
RC Diet
n=19 Participants
Reduced carbohydrate diet
RF Diet
n=17 Participants
Reduced fat diet
Change in Cumulative Fat Imbalance
-245 grams
Standard Error 21
-463 grams
Standard Error 37

SECONDARY outcome

Timeframe: 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.

Outcome measures

Outcome measures
Measure
RC Diet
n=20 Participants
Reduced carbohydrate diet
RF Diet
n=23 Participants
Reduced fat diet
Caudate Dopamine D2-like Receptor Binding Potential (D2BP)
28.2 ratio
Interval 26.48 to 29.86
24.9 ratio
Interval 22.95 to 26.92

SECONDARY outcome

Timeframe: 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.

Outcome measures

Outcome measures
Measure
RC Diet
n=20 Participants
Reduced carbohydrate diet
RF Diet
n=23 Participants
Reduced fat diet
Putamen Dopamine D2-like Receptor Binding Potential (D2BP)
30.7 ratio
Interval 28.61 to 32.7
27 ratio
Interval 25.14 to 28.93

SECONDARY outcome

Timeframe: 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.

Outcome measures

Outcome measures
Measure
RC Diet
n=20 Participants
Reduced carbohydrate diet
RF Diet
n=23 Participants
Reduced fat diet
Accumbens Dopamine D2-like Receptor Binding Potential (D2BP)
18.3 ratio
Interval 16.6 to 19.94
16.7 ratio
Interval 14.16 to 19.29

Adverse Events

Obese Reduced Carbohydrate

Serious events: 0 serious events
Other events: 0 other events
Deaths: 0 deaths

Obese Reduced Fat

Serious events: 0 serious events
Other events: 0 other events
Deaths: 0 deaths

Lean Control

Serious events: 0 serious events
Other events: 0 other events
Deaths: 0 deaths

Serious adverse events

Adverse event data not reported

Other adverse events

Adverse event data not reported

Additional Information

Kevin Hall, PhD

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

Phone: 3014028248

Results disclosure agreements

  • Principal investigator is a sponsor employee
  • Publication restrictions are in place