FEED-Cystic Fibrosis (FEED-CF) (FEED-CF)

Feeding Study to Optimize Endocrine Dysfunction in Cystic Fibrosis

The goal of this study is to determine the extent to which excess dietary sugars serve as a precipitating factor in glucose intolerance in adults with cystic fibrosis (CF), a population at especially high risk for a unique form of diabetes (CF-related diabetes, CFRD) and with standard-of-care dietary recommendations (high-calorie, high-fat) that conflict with recommendations for other forms of diabetes.

This trial will investigate if the typical high-sugar, high-fat CF diet plays a role in diabetes risk and visceral fat accumulation in people with CF. A total of 30 participants will get a low-added sugar, high-fat diet and the other 30 will get a standard CF diet with no sugar restrictions. Participants will be randomized to the diet group they are assigned. All foods will be provided for 8 weeks.

Study Overview

• Status: Recruiting
• Conditions: Cystic Fibrosis; Cystic Fibrosis-related Diabetes
• Intervention / Treatment: Other: Low-added sugar, high-fat diet; Other: High-added sugar, high-fat CF diet

Detailed Description

Approximately half of adults with cystic fibrosis (CF), a genetic disease, will develop diabetes. Dietary strategies shown to be successful in preventing or treating other forms of diabetes in people without CF contradict current nutritional recommendations for people with CF. The nutrition standard-of-care in CF is prescription of an unrestricted high-calorie, high-fat diet because of malnutrition. However, the standard CF diet translates to low-quality diets, with excess added sugars well-above general population recommendations. Also the investigators have shown that people with CF have more fat around their abdominal organs (called visceral fat) compared to healthy controls. The hypothesis is that the typical high-sugar, high-fat CF diet plays a role in diabetes risk and visceral fat accumulation in people with CF. In this study, the investigators will test if a low-added sugar diet improves risk markers for diabetes and decreases visceral fat over 8 weeks. The study will recruit 60 participants with CF. A total of 30 participants will get a low-added sugar, high-fat diet and the other 30 will get a standard CF diet with no sugar restrictions. Participants will be randomized to the diet group they are assigned. All foods will be provided for 8 weeks. There will be a total of 4 study visits at the Emory Hospital clinical research unit. These will include: 1) a screening visit with an oral glucose tolerance test with blood draws to determine if they already have diabetes, 2) a baseline visit for an insulin secretion test (called glucose-potentiated arginine (GPA) stimulation test) to assess risk for diabetes, as well as magnetic resonance imaging (MRI) testing to measure visceral fat, 3) a 4-week visit for another oral glucose tolerance test and in-person check-in, and 4) an 8-week visit for another GPA and MRI. Blood samples will be collected and banked. In addition to all meals provided for 8 weeks, participants will be compensated for their time and effort. Participants will be recruited from patients seen at the Emory CF Clinic. Informed consent will be performed prior to any study testing. The investigators hope this study will contribute to the development of new standardized nutrition guidelines for people living with CF.

• Study Type: Interventional
• Enrollment (Estimated): 60
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Jessica A Alvarez, PhD, RD; Phone Number: 404-727-1390; Email: jessica.alvarez@emory.edu
• Study Contact Backup: Name: Swati Zaveri, PhD; Phone Number: 440-778-8373; Email: swati.shital.zaveri@emory.edu

Study Locations

• United States
  • Georgia
    • Atlanta, Georgia, United States, 30322
      • Recruiting
      • Emory University Hospital
      • Contact: Swati Zaveri, PhD; Phone Number: 440-778-8373; Email: swati.shital.zaveri@emory.edu

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

1. Confirmed CF diagnosis
2. Ages 18 years and older
3. Baseline estimated daily total added sugar intake >16 tsp, as estimated from the Dietary Screener Questionnaire (DSQ).

Exclusion Criteria:

1. Nocturnal tube feeds
2. BMI <18.5 kg/m2
3. Life expectancy < 12 months
4. Confirmed diagnosis of CFRD
5. Screening OGTT showing fasting hyperglycemia (≥126 mg/dL)
6. Chronic steroid use
7. Current pregnancy or lactation
8. Inability/unwillingness to consume the majority of foods on the menu during the study period
9. MRI-incompatible metal that cannot be removed for testing
10. Uncontrolled exocrine pancreatic insufficiency/malabsorption
11. Clinically instability, defined as no changes in medical regimen (including medications and pulmonary exacerbations) for at least 21 days prior to study visit
12. Initiation of CFTR modulator within previous 8 weeks OR unstable changes in weight and lung function due to CFTR modulator use
13. Actively trying to gain or lose weight
14. Any food allergies or intolerances that cannot be accommodated
15. Any medical condition deemed by the a study physician or PI that may preclude completion of the study or interfere with primary end points.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Prevention
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Triple

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Low-added sugar, high-fat diet Arm; Patients will receive a low-added sugar, high-fat diet for 8 weeks. Study menus will be designed by registered dietitians using the Nutrient Database System for Research (NDSR) software program with a 2-wk rotation.Total kcal provided will be individually tailored to maintain body weight and adjusted throughout as needed. All foods (including snacks and drinks) for 8 wks will be delivered to participants' homes. Menus will be designed so that food will be delivered to subjects' homes every 3-4 days. It will be expected that participants consume only the foods provided by the study.	Other: Low-added sugar, high-fat diet; Consist of <5% kcal from added sugars as recommended by the American Heart Association, and the glycemic index will be 45 or lower (25% lower than typical CF diet). The macronutrient composition of both study diets will reflect the general CF recommendations for macronutrients: 35-40% of total kcal from fat and 15-20% total kcal from protein.
Active Comparator: Typical CF diet Arm; Patients will receive a high-added sugar, high-fat CF diet for 8 weeks. Study menus will be designed by registered dietitians using the Nutrient Database System for Research (NDSR) software program with a 2-wk rotation. Total kcal provided will be individually tailored to maintain body weight and adjusted throughout as needed. All foods (including snacks and drinks) for 8 wks will be delivered to participants' homes. Menus will be designed so that food will be delivered to subjects' homes every 3-4 days. It will be expected that participants consume only the foods provided by the study.	Other: High-added sugar, high-fat CF diet; Consist of ≥13% kcal from added sugars and the glycemic index will be >60. The macronutrient composition of both study diets will reflect the general CF recommendations for macronutrients: 35-40% of total kcal from fat and 15-20% total kcal from protein.; Other Names: Typical CF diet

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in acute insulin response to arginine (AIRarg) from baseline	Participants will undergo a Glucose-Potentiated Arginine Stimulation (GPA) Test after a 10-12 hour overnight fast to measure acute insulin (AIRarg) responses during a 230 and 340 mg/dl glucose clamp. This test will measure changes in beta cell secretory capacity.	Baseline and 8 weeks post intervention
Change in acute C-peptide (ACRarg) from baseline	Participants will undergo a Glucose-Potentiated Arginine Stimulation (GPA) Test after a 10-12 hour overnight fast to measure acute C-peptide (ACRarg) responses during a 230 and 340 mg/dl glucose clamp. This test will measure changes in beta cell secretory capacity.	Baseline and 8 weeks post intervention
Change in visceral adipose tissue from baseline	Dual energy X-ray absorptiometry (DEXA)-derived measurement of visceral adipose tissue (VAT) will be assessed with a GE Lunar iDXA machine. This will enable assessment of changes in body composition over the study.	Baseline and 8 weeks post intervention
Change in fasted plasma Eh[CySS] from baseline	Change in plasma Cysteine/Cystine Redox Potential (Eh[CySS]) will be measured.	Baseline and 8 weeks post intervention

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in Gastrointestinal Symptom Rating Scale (GSRS) scale	The GSRS is a 15 items combine into five symptom clusters: Reflux, Abdominal pain, Indigestion, Diarrhea and Constipation. Possible score range is 0-7, with 7 being the worst and 0 being the best (no symptoms).	Baseline and 8 weeks post intervention
Change in hepatic and pancreatic fat volume	Dual energy X-ray absorptiometry (DEXA)-derived measurement of visceral adipose tissue (VAT) for hepatic and pancreatic fat volume. Will be assessed with a GE Lunar iDXA machine.	Baseline and 8 weeks post intervention
Change in fasted plasma Eh[GSSG]	Change in plasma glutathione disulfide (GSSG) (Eh[CySS]) will be measured.	Baseline and 8 weeks post intervention

Collaborators and Investigators

• Sponsor: Emory University
• Collaborators: National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
• Investigators: Principal Investigator: Jessica A Alvarez, PhD, RD, Emory University

Publications and helpful links

General Publications

• Zaveri S, Stecenko A, Hunt WR, Goss A, Sharma P, Hartman TJ, Easley K, Chandler JD, Burley TM, Driggers C, Ciccarella A, Zhou H, Narlow K, Ziegler TR, Daley T, Vellanki P, Alvarez J. Low-added sugar dietary intervention study to mitigate glucose intolerance and improve body composition in adults with cystic fibrosis: a protocol of a double-blind, randomised study. BMJ Open. 2024 Dec 26;14(12):e092503. doi: 10.1136/bmjopen-2024-092503.

Study record dates

Study Major Dates

• Study Start (Actual): June 28, 2023
• Primary Completion (Estimated): June 30, 2028
• Study Completion (Estimated): June 30, 2028

Study Registration Dates

• First Submitted: February 21, 2023
• First Submitted That Met QC Criteria: March 2, 2023
• First Posted (Actual): March 13, 2023

Study Record Updates

• Last Update Posted (Actual): June 3, 2026
• Last Update Submitted That Met QC Criteria: June 1, 2026
• Last Verified: June 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Genetic Diseases, Inborn; Respiratory Tract Diseases; Digestive System Diseases; Lung Diseases; Infant, Newborn, Diseases; Pancreatic Diseases; Congenital, Hereditary, and Neonatal Diseases and Abnormalities; Cystic Fibrosis; Diet, Food, and Nutrition; Physiological Phenomena; Nutritional Physiological Phenomena; Diet; Diet, High-Fat
• Other Study ID Numbers: STUDY00004517; 1R01DK133523-01 (U.S. NIH Grant/Contract); 2025P010830 (Other Identifier: Emory IRB)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: Actual clinical study data in raw and summary form, with protected health information removed, as well as access to the study database, will be available for reference of qualified professional colleagues and auditors up to 10 years after study publication. With appropriate subject informed consent, clinical and research data obtained from this study will be deposited into the Georgia CF Data Warehouse of the NDDK P30-supported Georgia Cystic Fibrosis Clinical and Translational Core Center.
• IPD Sharing Time Frame: After final publication date
• IPD Sharing Access Criteria: Qualified researchers for analyses of original study endpoints not pre-specified as primary, secondary, or exploratory that contact the investigators.
• IPD Sharing Supporting Information Type: STUDY_PROTOCOL

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