Dietary Fiber: Is it the Missing Link in Achieving Long Term Behavior Change?

The overall objective of this three-arm randomized controlled trial is to compare a dietary fiber-focused behavioral intervention to standard weight loss education for improving eating-related behavior and cognition, weight, and metabolic markers of chronic disease risk in a population of adults with obesity.

Study Overview

• Status: Active, not recruiting
• Conditions: Obesity
• Intervention / Treatment: Behavioral: Standard Weight Loss Education; Behavioral: Fiber Intervention

• Study Type: Interventional
• Enrollment (Actual): 63
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • Oklahoma
    • Stillwater, Oklahoma, United States, 74078
      • Oklahoma State University

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• 18-65 years of age
• Dietary fiber intake ≤25 grams/day
• Self-reported BMI ≥30 kg/m2
• Willingness to attend in-person education sessions
• Willingness to avoid taking supplemental digestive aids (e.g., alpha-galactosidase (Beano®),
• Willingness to provide informed consent.

Exclusion Criteria:

• Metabolic, digestive, or allergic conditions or reactions that preclude consumption of whole food or food groups (e.g., irritable bowel syndrome, diverticulosis)
• History of gastric bypass surgery
• Currently taking glucagon like glucagon-like peptide-1 (GLP-1) Receptor Agonists
• Self-reported history of a diagnosed eating disorder
• Chronic disease (other than obesity)
• Pregnancy or lactation
• Use of tobacco or electronic smoking products
• Taking a pre-, pro-, or syn-biotic supplement
• Enrollment in another weight loss or diet intervention

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Factorial Assignment
• Masking: None (Open Label)

Number of Arms

3

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Fiber Intervention; Individuals in this arm will be given instruction on how to increase fiber intake,	Behavioral: Fiber Intervention; Group education and phone-based motivational interviewing to gradually increase dietary fiber consumption to 30-35 grams per day.
Active Comparator: Standard Weight Loss Education; Individuals in this arm will be given standard weight loss education	Behavioral: Standard Weight Loss Education; Group education and phone-based motivational interviewing to promote current evidence-based behaviors to promote weight loss via achieving a negative energy balance.
Experimental: Fiber Intervention + Standard Weight Loss Education; Individuals in this arm will be given education on both fiber and standard weight loss	Behavioral: Standard Weight Loss Education; Group education and phone-based motivational interviewing to promote current evidence-based behaviors to promote weight loss via achieving a negative energy balance.; Behavioral: Fiber Intervention; Group education and phone-based motivational interviewing to gradually increase dietary fiber consumption to 30-35 grams per day.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Body weight	Measure of body weight/mass	Measured at baseline (time 1, month 0), post-intervention (time 2, month 15), and post-observation (time 3, month 27)

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Body composition (fat mass, lean mass)	Dual x-ray absorptiometry (DEXA) scans	Measured at baseline (time 1, month 0) and post-observation (time 3, month 27)
Fecal short chain fatty acids	Taken from fecal samples collected at home	Measured at baseline (time 1, month 0), post-intervention (time 2, month 15), and post-observation (time 3, month 27)
Fecal bacteria measured using 16S ribosomal ribonucleic acid (rRNA) sequencing	Will include measures of diversity, abundance, etc.	Measured at baseline (time 1, month 0), post-intervention (time 2, month 15), and post-observation (time 3, month 27)
Total Cholesterol	Measured via blood samples (unit= milligram/deciliter (mg/dL))	Measured at baseline (time 1, month 0), post-intervention (time 2, month 15), and post-observation (time 3, month 27)
Fasting blood glucose	Measured via blood samples (unit=mg/dL)	Measured at baseline (time 1, month 0), post-intervention (time 2, month 15), and post-observation (time 33, month 27)
Healthy Eating Index Scores measured using Health Eating Index 2020 (HEI-2020)	Taken from 3 day diet records (score range=0-100, higher=better diet quality)	Measured at baseline (time 1, month 0), post-intervention (time 2, month 15), and post-observation (time 3, month 27)
Three-Factor Eating Questionnaire	Resulting scores in uncontrolled eating (range=9-36), cognitive restraint (range=3-12), and emotional eating (range=6-24); higher scores indicate more of that particular eating behavior	Measured at baseline (time 1, month 0), post-intervention (time 2, month 15), and post-observation (time 3, month 27)
Implicit Association Test	Represented with a total D variable (No range, but more negative = greater preference for unprocessed food)	Measured at baseline (time 1, month 0), post-intervention (time 2, month 15), and post-observation (time 3, month 27)
Behavioral Inhibition System/Behavioral Approach System (BIS/BAS) Scale	Score ranges from 20 to 80, with higher scores indicating greater behavioral inhibition and behavioral activation	Measured at baseline (time 1, month 0), post-intervention (time 2, month 15), and post-observation (time 3, month 27)
Executive Function: Tower Test (Delis-Kaplan Executive Function System)	Total Achievement Score (range=0-30, higher = higher executive function)	Measured at baseline (time 1, month 0), post-intervention (time 2, month 15), and post-observation (time 3, month 27)
Executive Function: Color-Word Interference Test (Delis-Kaplan Executive Function System)	Scaled inhibition/switching scores (score range=1-19, higher = higher executive function)	Measured at baseline (time 1, month 0), post-intervention (time 2, month 15), and post-observation (time 3, month 27)
Skin Carotenoid scores measured via the Veggie Meter	Veggie Meter; score range 0-800 (higher=greater skin carotenoids (i.e., consumption of more fruits/vegetables)	Measured at baseline (time 1, month 0), post-intervention (time 2, month 15), and post-observation (time 3, month 27)
High-density lipoprotein (HDL) cholesterol	Measured via blood samples (unit=mg/dL)	Measured at baseline (time 1, month 0), post-intervention (time 2, month 15), and post-observation (time 3, month 27)
Low-density lipoprotein (LDL) cholesterol	Measured via blood samples (unit=mg/dL)	Measured at baseline (time 1, month 0), post-intervention (time 2, month 15), and post-observation (time 3, month 27)

Collaborators and Investigators

• Sponsor: Oklahoma State University

Study record dates

Study Major Dates

• Study Start (Actual): July 10, 2023
• Primary Completion (Estimated): January 31, 2026
• Study Completion (Estimated): February 28, 2026

Study Registration Dates

• First Submitted: July 28, 2023
• First Submitted That Met QC Criteria: January 24, 2024
• First Posted (Actual): January 29, 2024

Study Record Updates

• Last Update Posted (Estimated): September 29, 2025
• Last Update Submitted That Met QC Criteria: September 23, 2025
• Last Verified: September 1, 2025

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Nutrition Disorders; Overnutrition; Body Weight; Overweight; Pathological Conditions, Signs and Symptoms; Nutritional and Metabolic Diseases; Signs and Symptoms; Obesity
• Other Study ID Numbers: IRB-23-59-STW

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No