The Precision Nutrition New York Study (PNNY)

Optimizing Dietary Fiber Eating Patterns to Prevent Obesity and Resulting Metabolic Disorders

Dietary fiber has been shown to have beneficial effects on human health through its impact on microbes present in the gut. However, these effects can vary between individuals, and everyone may not reap the same health benefits by eating the same sources of fiber. Factors predicting how an individual's gut microbes as well as the beneficial metabolites produced by these microbes change in response to different sources of fiber would be helpful in developing precision nutrition approaches that maximize the benefits of dietary fiber. The objective of this study is to evaluate candidate predictors of gut microbiota response to fiber sources from either whole grains or fruits and vegetables.

Study Overview

• Status: Recruiting
• Conditions: Body Weight Changes; Body Composition Changes
• Intervention / Treatment: Other: Whole Grain Intervention then fruits and vegetables; Other: Fruit and Vegetable Intervention and then whole grains

• Study Type: Interventional
• Enrollment (Estimated): 15
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Angela Poole; Phone Number: 607-255-8796; Email: pnnystudy@cornell.edu
• Study Contact Backup: Name: Colette Strathman

Study Locations

• United States
  • New York
    • Ithaca, New York, United States, 14850
      • Recruiting
      • Cornell University
      • Contact: Angela Poole, PhD; Phone Number: 607-255-8796; Email: pnnystudy@cornell.edu
      • Principal Investigator: Angela Poole, PhD

Participation Criteria

Eligibility Criteria

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

Description

Inclusion Criteria:

• Age is between 21-50 years
• BMI is between 25-30. You can check your BMI here: https://www.cdc.gov/bmi/adult-calculator/index.html
• Must be able to have height, weight, waist, and hip circumference, and body composition measured during the study
• Must be able to provide saliva samples.
• Must be able to provide a phone number and email address at which the study investigators can contact for study-related matters.
• Must be able to increase dietary fiber intake to the recommended level following the instructions on the USDA MyPlate website: https://www.myplate.gov/myplate-plan
• Must be able to provide food records of everything consumed (food, beverage, and supplements) on one weekday and one weekend day (example Tuesday, Saturday) every week during the study. This will be done using an online survey.
• Must be able to provide 10 stool samples over 11 weeks of the study duration. 18) Must have stable weight (within ±3% of usual body weight) for the last two months.
• Must be able to to take an online survey to assess recent dietary fiber intake to determine eligibility.

Exclusion Criteria:

• Electronic medical implant, for example, a pacemaker.
• An existing, UNTREATED, thyroid condition.
• Use of systemic antibiotics (intravenous injection, intramuscular, or oral) within the last 4 months.
• An acute disease at the time of enrollment (Acute disease is defined as the presence of a moderate or severe illness with or without fever).
• A chronic, clinically significant (unresolved, requiring ongoing medical management or medication) pulmonary, cardiovascular, gastrointestinal, hepatic, or renal functional abnormality.
• Any suspected state of immunosuppression or immunodeficiency including HIV.

• A history of active UNTREATED gastrointestinal disorders or diseases including

  1. Inflammatory bowel disease (IBD)
  2. Ulcerative colitis (mild-moderate-severe)
  3. Crohn's or celiac disease
  4. Indeterminate colitis
  5. Irritable bowel syndrome (IBS) (moderate-severe)
  6. Persistent, infectious gastroenteritis, colitis or gastritis
  7. Persistent or chronic diarrhea of unknown etiology
  8. Clostridium difficile infection (recurrent)
  9. Chronic constipation
• Previously had bariatric surgery.
• An unstable dietary history as defined by major changes in diet during the previous month. For example, elimination or significantly increased intake of a major food group in the diet.
• Recent history of chronic alcohol consumption defined as more than 5 drinks (or servings) of alcohol per day.
• Female participants: pregnant/lactating.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Supportive Care
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Experimental: Group A: Whole grains then fruits and vegetables; Whole grain intervention then fruits and vegetables	Other: Whole Grain Intervention then fruits and vegetables; TREATMENT 1: Participants will eat whole grains that add up to the required daily fiber needs. Investigators will provide participants with these products. Participants will follow this intervention for a set period of time. The beginning of the intervention will include a ramp up phase when they eat half of the daily fiber needs to prevent any gastrointestinal distress from suddenly consuming a higher fiber diet than usual. TREATMENT 2: Participants will eat fruits and vegetables that add up to the required daily fiber needs. Investigators will provide participants with these products. Participants will follow this intervention for a set period of time. The beginning of the intervention will include a ramp up phase when participants eat half of the daily fiber needs to prevent any gastrointestinal distress from suddenly consuming a higher fiber diet than usual.
Experimental: Experimental: Group B: Fruits and vegetables then whole grains; Fruits and vegetables intervention then whole grains	Other: Fruit and Vegetable Intervention and then whole grains; TREATMENT 1: Participants will eat fruits and vegetables that add up to the required daily fiber needs. Investigators will provide participants with these products. Participants will follow this intervention for a set period of time. The beginning of the intervention will include a ramp up phase when participants eat half of the daily fiber needs to prevent any gastrointestinal distress from suddenly consuming a higher fiber diet than usual. TREATMENT 2: Participants will eat whole grains that add up to the required daily fiber needs. Investigators will provide participants with these products. Participants will follow this intervention for a set period of time. The beginning of the intervention will include a ramp up phase when they eat half of the daily fiber needs to prevent any gastrointestinal distress from suddenly consuming a higher fiber diet than usual.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Body weight changes	For each intervention (whole grains & fruits and vegetables), investigators will measure change in body weight in kg = Post-intervention minus Pre-intervention	3-4 weeks
Body fat percentage changes	For each intervention (whole grains & fruits and vegetables), investigators will measure change in fat percentage = Post-intervention minus Pre-intervention	3-4 weeks

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Gut microbiome measured by 16S rRNA gene sequencing	For each intervention (whole grains & fruits and vegetables), investigators will calculate changes in relative abundance (proportion) of each gut bacterium from Pre-intervention to Post-intervention.	3-4 weeks
Fecal short-chain fatty acid concentrations (SCFAs)	For each intervention (whole grains & fruits and vegetables), investigators will measure change in SCFA concentrations = Post-intervention minus Pre-intervention. We will report the SCFAs acetate, butyrate, and propionate.	3-4 weeks

Collaborators and Investigators

• Sponsor: Cornell University

Study record dates

Study Major Dates

• Study Start (Actual): January 13, 2025
• Primary Completion (Estimated): October 1, 2025
• Study Completion (Estimated): December 31, 2025

Study Registration Dates

• First Submitted: January 6, 2025
• First Submitted That Met QC Criteria: January 14, 2025
• First Posted (Actual): January 16, 2025

Study Record Updates

• Last Update Posted (Actual): July 11, 2025
• Last Update Submitted That Met QC Criteria: July 9, 2025
• Last Verified: July 1, 2025

More Information

Terms related to this study

• Keywords: gut microbiome; fruits; vegetables; gut microbiota; dietary fiber; short-chain fatty acids; SCFAs; whole grains
• Additional Relevant MeSH Terms: Body Weight; Body Weight Changes
• Other Study ID Numbers: IRB0147806; 7005865 (Other Grant/Funding Number: USDA NIFA Hatch)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED
• IPD Plan Description: We will NEVER share de-identified data about the participants. Our previous publications show aggregated data results. This study is identical to our previous in design, sample types, and data being collected. We shared the de-identified 16S rRNA sequence data of the participants in a public database as requested by the journals. When requested by a journal, we have shared eligibility criteria. Some journals may require us to share our statistical code.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No