Overnight Fasting After Completion of Therapy: The OnFACT Study

June 29, 2026 updated by: Memorial Sloan Kettering Cancer Center
The purpose of this study is to test whether regularly not eating for at least 14 hours overnight ("intermittent fasting") is feasible and can improve blood sugar.

Study Overview

Status

Active, not recruiting

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Actual)

28

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • United States
    • New York
      • New York, New York, United States, 10065
        • Memorial Sloan Kettering Cancer Center

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

18 years and older (Adult, Older Adult)

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Body mass index is ≥ 18.5 kg/m^2
  • History of treatment for cancer or related illness diagnosed at ≤ 25 years old
  • Off cytotoxic therapy for primary cancer ≥ 2 years
  • Not receiving cytotoxic therapy (chemotherapy, external beam radiation therapy) at the time of study enrollment
  • History of radiation to the chest, abdomen or total body
  • Current age ≥18 years
  • English-speaking
  • Personal phone with SMS text messaging capability
  • Willingness to wear an mHealth device, such as a FitBit, for two 7-day periods
  • Able to perform all study requirements

Exclusion Criteria:

  • Use of any antidiabetic, weight loss, or appetite control medication
  • Use of any other medication that could impact dietary intake, such as prednisone
  • Currently fasts 12 hours or more by self-report
  • Unable to fast due to medical reason such as pregnancy

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Prevention
  • Allocation: Randomized
  • Interventional Model: Single Group Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: prolonged overnight fasting
Participants randomized to the fasting arm will be instructed on how to use the SMS texting app to indicate the beginning and end of the nightly fast. In the first 2-4 weeks following the first overnight fast, intervention participants will complete three phone calls with study staff trained in motivational interviewing. These calls will be used to reinforce the prolonged overnight fasting instructions, identify barriers to prolonged overnight fasting, and support successes where they have occurred.
Other: prolonged overnight fasting
Three phone calls using motivational interviewing, support via SMS text.
Active Comparator: usual care
Participants randomized to the usual care arm will be instructed to eat a heart-healthy diet and exercise for at least 30 minutes five days a week, which is usual counseling in our clinics.
Other: usual care
Eat a heart-healthy diet and exercise for at least 30 minutes five days a week

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Participation completion
Time Frame: 6 months
Proportion of registered participants who successfully complete the 6-month intervention
6 months

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
measure of glucose metabolism
Time Frame: 6 months
Assess the effect of prolonged overnight fasting on glucose metabolism, measured by glycosylated hemoglobin (HbA1c).
6 months

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Memorial Sloan Kettering Cancer Center

Collaborators

Rockefeller University

Investigators

  • Principal Investigator: Danielle Friedman, MD, MS, Memorial Sloan Kettering Cancer Center

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

Helpful Links

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

April 27, 2018

Primary Completion (Estimated)

April 1, 2027

Study Completion (Estimated)

April 1, 2027

Study Registration Dates

First Submitted

May 1, 2018

First Submitted That Met QC Criteria

May 1, 2018

First Posted (Actual)

May 14, 2018

Study Record Updates

Last Update Posted (Actual)

July 1, 2026

Last Update Submitted That Met QC Criteria

June 29, 2026

Last Verified

June 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 18-199

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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