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Diet, Insulin Sensitivity, and Postprandial Metabolism (TEF)

Primary Purpose

Overweight, Obesity, Insulin Resistance

Status
Completed
Phase
Not Applicable
Locations
United States
Study Type
Interventional
Intervention
Plant-based diet
Control Diet
Sponsored by
Physicians Committee for Responsible Medicine
About
Eligibility
Locations
Arms
Outcomes
Full info

About this trial

This is an interventional treatment trial for Overweight focused on measuring Plant-based diet, Obesity, Insulin sensitivity, Intracellular lipid, Postprandial metabolism, Vegan diet, Beta-cell function

Eligibility Criteria

18 Years - undefined (Adult, Older Adult)All SexesDoes not accept healthy volunteers

Inclusion Criteria:

  • Men and women age ≥18 years of age
  • Body mass index 28-40 kg/m2

Exclusion Criteria:

  1. Diabetes mellitus, type 1 or 2, history of diabetes mellitus or of any endocrine condition that would affect body weight, such as thyroid disease, pituitary abnormality, or Cushing's syndrome
  2. Smoking during the past six months
  3. Alcohol consumption of more than 2 drinks per day or the equivalent, episodic increased drinking (e.g., more than 2 drinks per day on weekends), or a history of alcohol abuse or dependency followed by any current use
  4. Use of recreational drugs in the past 6 months
  5. Use within the preceding six months of medications that affect appetite or body weight, such as estrogens or other hormones, thyroid medications, systemic steroids, antidepressants (tricyclics, monoamine oxidase inhibitors (MAOIs), selective serotonin reuptake inhibitors (SSRIs), antipsychotics, lithium, anticonvulsants, appetite suppressants or other weight-loss drugs, herbs for weight loss or mood, St. John's wort, ephedra, beta blockers
  6. Pregnancy or intention to become pregnant during the study period
  7. Unstable medical or psychiatric illness
  8. Evidence of an eating disorder
  9. Likely to be disruptive in group sessions
  10. Already following a low-fat, vegan diet
  11. Lack of English fluency
  12. Inability to maintain current medication regimen
  13. Inability or unwillingness to participate in all components of the study
  14. Intention to follow another weight-loss method during the trial

Sites / Locations

  • Physicians Committee for Responsible Medicine

Arms of the Study

Arm 1

Arm 2

Arm Type

Active Comparator

Active Comparator

Arm Label

Plant-based diet

Control diet

Arm Description

The diet group will be asked to follow a low-fat, vegan diet for 16 weeks

Half of the participants will be asked to continue their usual diets for the 16-week study period.

Outcomes

Primary Outcome Measures

Body weight in kg
Anticipated weight-loss for intervention group compared with control group. Weight and height will be combined to report BMI in kg/m^2
Fat mass in grams
Anticipated weight-loss for intervention group compared with control group.
Visceral fat in cm^3
Anticipated weight-loss for intervention group compared with control group.
Changes in intramyocellular and/or intrahepatocellular lipid
A subset of participants will be selected for magnetic resonance (MR) spectroscopy studies quantifying hepatic lipid and/or intramyocellular and/or contents in order to provide data regarding possible causal relationships between dietary changes, ectopic lipid, and insulin sensitivity. Selected individuals with varying degrees of insulin-resistance in both groups will be assessed before and after the intervention period. These magnetic resonance spectroscopy (MRS) studies will take place at the Magnetic Research Center at Yale University School of Medicine, New Haven, CT.
Insulin resistance
Insulin resistance will be assessed by the Homeostatic Model Assessment (HOMA) index.
Resting Energy Expenditure (REE)
Participants will be asked to report to the laboratory within 60 minutes of waking and after a 12-hour fast. Following 30 minutes of quiet rest in a dimly lit room, pulse, respiratory rate, and body temperature will be measured. REE will be measured for 20 minutes through indirect calorimetry (COSMED Metabolic Company Quark Resting Metabolic Rate (RMR), Chicago, IL) utilizing a ventilated hood system. The laboratory temperature will be maintained at 23 degrees C throughout, and precautions will be taken to minimize any disturbances that could affect the metabolic rate. For premenopausal women, measures will be timed so as to occur in the luteal phase of the menstrual cycle.
Postprandial metabolism
Participants will be asked to report to the laboratory within 60 minutes of waking and after a 12-hour fast. Postprandial metabolism will be measured for three hours after the standard meal. For premenopausal women, measures will be timed so as to occur in the luteal phase of the menstrual cycle.

Secondary Outcome Measures

Beta-cell function as measured by glucose (mmmol/L)
A standard meal test will be performed after an overnight fast. Plasma glucose, will be measured at 0, 30, 60, 120, and 180 min for a total of 3-hours over a 16-week period. Glucose, insulin and C-peptide will combined and analyzed to report Beta-cell function.
Beta-cell function as measured by insulin (pmol/L)
A standard meal test will be performed after an overnight fast. Plasma insulin will be measured at 0, 30, 60, 120, and 180 min for a total of 3-hours over a 16-week period. Glucose, insulin and C-peptide will combined and analyzed to report Beta-cell function.
Beta-cell function as measured by C-peptide (ng/mL)
A standard meal test will be performed after an overnight fast. Plasma C-peptide will be measured at 0, 30, 60, 120, and 180 min for a total of 3-hours over a 16-week period. Glucose, insulin and C-peptide will combined and analyzed to report Beta-cell function.
Microbiome Analysis
Microbiome analysis from participant-provided stool sample. Analysis from uBiome Biotechnology company in a subset of participants. Anticipated changes in the dietary intervention group include changes in the microbiome composition that correlate with changes in insulin sensitivity.
Endothelial function
Endothelial function will be measured using the EndoPAT, a proprietary diagnostic device for functional vascular health assessment, in a subset of participants.
Diet Assessment Recall Questionnaire
24-hour multi-pass dietary recalls will be used to assess dietary adherence to assist study personnel in working with individuals who need additional teaching or support.
The Effect of Fat Quantity & Quality on Body Composition, Insulin Resistance, & Insulin Secretion
Regression Analysis will be used to assess The Effect of Fat Quantity & Quality on Body Composition, Insulin Resistance, & Insulin Secretion
The Effect of Carbohydrate Quantity & Quality on Body Composition & Insulin Resistance
Regression Analysis will be used to assess The Effect of Carbohydrate Quantity & Quality on Body Composition & Insulin Resistance
The Effect of Protein Quantity & Quality on Body Composition, Insulin Resistance, & Insulin Secretion
Regression Analysis will be used to assess The Effect of Protein Quantity & Quality on Body Composition, Insulin Resistance, & Insulin Secretion
Levels of Advanced Glycosylation Endproducts (AGEs)
An AGE reader will be used to measure the Levels of the AGEs in the skin
Race Disparities
Compare the effectiveness of the vegan diet in Blacks vs. Whites in all the primary outcomes
Dietary Advanced Glycation End Products (AGEs)
Explore the effectiveness of a vegan diet in reducing dietary AGEs.
Food costs
Food costs will be assessed, using the U.S. Department of Agriculture Thrifty Food Plan, 2021, at baseline and 16 weeks.
PDI, hPDI, uPDI
Assess the total plant-based index (PDI), healthy PDI, and unhealthy PDI, and their relationship with weight loss
Ultraprocessed foods
The consumption of ultraprocessed foods will be assessed, using the NOVA classification, at baseline and 16 weeks.

Full Information

First Posted
October 17, 2016
Last Updated
July 17, 2023
Sponsor
Physicians Committee for Responsible Medicine
Collaborators
Yale University
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1. Study Identification

Unique Protocol Identification Number
NCT02939638
Brief Title
Diet, Insulin Sensitivity, and Postprandial Metabolism
Acronym
TEF
Official Title
A Randomized, Controlled Trial on Diet, Insulin Sensitivity, and Postprandial Metabolism
Study Type
Interventional

2. Study Status

Record Verification Date
July 2023
Overall Recruitment Status
Completed
Study Start Date
October 2016 (Actual)
Primary Completion Date
December 2018 (Actual)
Study Completion Date
January 9, 2019 (Actual)

3. Sponsor/Collaborators

Responsible Party, by Official Title
Sponsor
Name of the Sponsor
Physicians Committee for Responsible Medicine
Collaborators
Yale University

4. Oversight

Data Monitoring Committee
Yes

5. Study Description

Brief Summary
This randomized, controlled trial aims to elucidate the mechanisms by which a plant-based dietary intervention causes weight loss. Using a low-fat, plant-based diet for 16 weeks, along with an untreated control for comparison, the study will measure changes in body weight, body composition, intramyocellular and/or intrahepatocellular lipid, and changes in association to body weight.
Detailed Description
In a 16-week trial, overweight adults will be randomly assigned to two groups. Changes in body weight, body composition, intramyocellular and/or intrahepatocellular lipid, and changes in association to body weight will be measured among other outcomes. The Intervention Group will follow a low-fat, vegan diet and will receive weekly classes and support. The Control Group will be asked to follow a conventional control diet. This study conducts a pilot sub-study to test the hypothesis that changes in insulin sensitivity and beta-cell function observed in response to a diet intervention correlate with changes in intramyocellular and/or intrahepatocellular lipid. Another sub-study assesses the association between metabolic outcomes and gut microbiome. One additional sub-study is looking for associations between metabolic outcomes and endothelial function.

6. Conditions and Keywords

Primary Disease or Condition Being Studied in the Trial, or the Focus of the Study
Overweight, Obesity, Insulin Resistance
Keywords
Plant-based diet, Obesity, Insulin sensitivity, Intracellular lipid, Postprandial metabolism, Vegan diet, Beta-cell function

7. Study Design

Primary Purpose
Treatment
Study Phase
Not Applicable
Interventional Study Model
Parallel Assignment
Masking
None (Open Label)
Allocation
Randomized
Enrollment
220 (Actual)

8. Arms, Groups, and Interventions

Arm Title
Plant-based diet
Arm Type
Active Comparator
Arm Description
The diet group will be asked to follow a low-fat, vegan diet for 16 weeks
Arm Title
Control diet
Arm Type
Active Comparator
Arm Description
Half of the participants will be asked to continue their usual diets for the 16-week study period.
Intervention Type
Other
Intervention Name(s)
Plant-based diet
Other Intervention Name(s)
Vegan diet
Intervention Description
Weekly instructions will be given to the participants in the intervention group about following vegan diet.
Intervention Type
Other
Intervention Name(s)
Control Diet
Intervention Description
Participants will be asked to continue their usual diets for the 16-week study period.
Primary Outcome Measure Information:
Title
Body weight in kg
Description
Anticipated weight-loss for intervention group compared with control group. Weight and height will be combined to report BMI in kg/m^2
Time Frame
16 weeks
Title
Fat mass in grams
Description
Anticipated weight-loss for intervention group compared with control group.
Time Frame
16 weeks
Title
Visceral fat in cm^3
Description
Anticipated weight-loss for intervention group compared with control group.
Time Frame
16 weeks
Title
Changes in intramyocellular and/or intrahepatocellular lipid
Description
A subset of participants will be selected for magnetic resonance (MR) spectroscopy studies quantifying hepatic lipid and/or intramyocellular and/or contents in order to provide data regarding possible causal relationships between dietary changes, ectopic lipid, and insulin sensitivity. Selected individuals with varying degrees of insulin-resistance in both groups will be assessed before and after the intervention period. These magnetic resonance spectroscopy (MRS) studies will take place at the Magnetic Research Center at Yale University School of Medicine, New Haven, CT.
Time Frame
16 Weeks
Title
Insulin resistance
Description
Insulin resistance will be assessed by the Homeostatic Model Assessment (HOMA) index.
Time Frame
16 weeks
Title
Resting Energy Expenditure (REE)
Description
Participants will be asked to report to the laboratory within 60 minutes of waking and after a 12-hour fast. Following 30 minutes of quiet rest in a dimly lit room, pulse, respiratory rate, and body temperature will be measured. REE will be measured for 20 minutes through indirect calorimetry (COSMED Metabolic Company Quark Resting Metabolic Rate (RMR), Chicago, IL) utilizing a ventilated hood system. The laboratory temperature will be maintained at 23 degrees C throughout, and precautions will be taken to minimize any disturbances that could affect the metabolic rate. For premenopausal women, measures will be timed so as to occur in the luteal phase of the menstrual cycle.
Time Frame
16 weeks
Title
Postprandial metabolism
Description
Participants will be asked to report to the laboratory within 60 minutes of waking and after a 12-hour fast. Postprandial metabolism will be measured for three hours after the standard meal. For premenopausal women, measures will be timed so as to occur in the luteal phase of the menstrual cycle.
Time Frame
16 weeks
Secondary Outcome Measure Information:
Title
Beta-cell function as measured by glucose (mmmol/L)
Description
A standard meal test will be performed after an overnight fast. Plasma glucose, will be measured at 0, 30, 60, 120, and 180 min for a total of 3-hours over a 16-week period. Glucose, insulin and C-peptide will combined and analyzed to report Beta-cell function.
Time Frame
16 weeks
Title
Beta-cell function as measured by insulin (pmol/L)
Description
A standard meal test will be performed after an overnight fast. Plasma insulin will be measured at 0, 30, 60, 120, and 180 min for a total of 3-hours over a 16-week period. Glucose, insulin and C-peptide will combined and analyzed to report Beta-cell function.
Time Frame
16 weeks
Title
Beta-cell function as measured by C-peptide (ng/mL)
Description
A standard meal test will be performed after an overnight fast. Plasma C-peptide will be measured at 0, 30, 60, 120, and 180 min for a total of 3-hours over a 16-week period. Glucose, insulin and C-peptide will combined and analyzed to report Beta-cell function.
Time Frame
16 weeks
Title
Microbiome Analysis
Description
Microbiome analysis from participant-provided stool sample. Analysis from uBiome Biotechnology company in a subset of participants. Anticipated changes in the dietary intervention group include changes in the microbiome composition that correlate with changes in insulin sensitivity.
Time Frame
16 weeks
Title
Endothelial function
Description
Endothelial function will be measured using the EndoPAT, a proprietary diagnostic device for functional vascular health assessment, in a subset of participants.
Time Frame
16 weeks
Title
Diet Assessment Recall Questionnaire
Description
24-hour multi-pass dietary recalls will be used to assess dietary adherence to assist study personnel in working with individuals who need additional teaching or support.
Time Frame
16 weeks
Title
The Effect of Fat Quantity & Quality on Body Composition, Insulin Resistance, & Insulin Secretion
Description
Regression Analysis will be used to assess The Effect of Fat Quantity & Quality on Body Composition, Insulin Resistance, & Insulin Secretion
Time Frame
16 Weeks
Title
The Effect of Carbohydrate Quantity & Quality on Body Composition & Insulin Resistance
Description
Regression Analysis will be used to assess The Effect of Carbohydrate Quantity & Quality on Body Composition & Insulin Resistance
Time Frame
16 Weeks
Title
The Effect of Protein Quantity & Quality on Body Composition, Insulin Resistance, & Insulin Secretion
Description
Regression Analysis will be used to assess The Effect of Protein Quantity & Quality on Body Composition, Insulin Resistance, & Insulin Secretion
Time Frame
16 Weeks
Title
Levels of Advanced Glycosylation Endproducts (AGEs)
Description
An AGE reader will be used to measure the Levels of the AGEs in the skin
Time Frame
16 Weeks
Title
Race Disparities
Description
Compare the effectiveness of the vegan diet in Blacks vs. Whites in all the primary outcomes
Time Frame
16 weeks
Title
Dietary Advanced Glycation End Products (AGEs)
Description
Explore the effectiveness of a vegan diet in reducing dietary AGEs.
Time Frame
16 weeks
Title
Food costs
Description
Food costs will be assessed, using the U.S. Department of Agriculture Thrifty Food Plan, 2021, at baseline and 16 weeks.
Time Frame
16 weeks
Title
PDI, hPDI, uPDI
Description
Assess the total plant-based index (PDI), healthy PDI, and unhealthy PDI, and their relationship with weight loss
Time Frame
16 weeks
Title
Ultraprocessed foods
Description
The consumption of ultraprocessed foods will be assessed, using the NOVA classification, at baseline and 16 weeks.
Time Frame
16 weeks

10. Eligibility

Sex
All
Minimum Age & Unit of Time
18 Years
Accepts Healthy Volunteers
No
Eligibility Criteria
Inclusion Criteria: Men and women age ≥18 years of age Body mass index 28-40 kg/m2 Exclusion Criteria: Diabetes mellitus, type 1 or 2, history of diabetes mellitus or of any endocrine condition that would affect body weight, such as thyroid disease, pituitary abnormality, or Cushing's syndrome Smoking during the past six months Alcohol consumption of more than 2 drinks per day or the equivalent, episodic increased drinking (e.g., more than 2 drinks per day on weekends), or a history of alcohol abuse or dependency followed by any current use Use of recreational drugs in the past 6 months Use within the preceding six months of medications that affect appetite or body weight, such as estrogens or other hormones, thyroid medications, systemic steroids, antidepressants (tricyclics, monoamine oxidase inhibitors (MAOIs), selective serotonin reuptake inhibitors (SSRIs), antipsychotics, lithium, anticonvulsants, appetite suppressants or other weight-loss drugs, herbs for weight loss or mood, St. John's wort, ephedra, beta blockers Pregnancy or intention to become pregnant during the study period Unstable medical or psychiatric illness Evidence of an eating disorder Likely to be disruptive in group sessions Already following a low-fat, vegan diet Lack of English fluency Inability to maintain current medication regimen Inability or unwillingness to participate in all components of the study Intention to follow another weight-loss method during the trial
Overall Study Officials:
First Name & Middle Initial & Last Name & Degree
Neal D Barnard, M.D.
Organizational Affiliation
President
Official's Role
Principal Investigator
Facility Information:
Facility Name
Physicians Committee for Responsible Medicine
City
Washington
State/Province
District of Columbia
ZIP/Postal Code
20016
Country
United States

12. IPD Sharing Statement

Plan to Share IPD
Undecided
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Diet, Insulin Sensitivity, and Postprandial Metabolism

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