A Fasting Pilot Study for Long COVID

February 10, 2026 updated by: Université de Sherbrooke

A Prospective Pilot Study to Evaluate the Feasibility of Prolonged Fasting for the Treatment of Long COVID Patients

Background Long COVID (LC) is a chronic multisystemic condition which substantially impact the quality of life. Despite the staggering burden of LC, there is still no effective treatment.

Because fasting promotes anti-inflammatory and antioxidant responses, which are involved in the pathophysiology of LC, we hypothesized that it might improve daily functioning and health-related quality of life in patients with LC.

The aim of this single center, one arm, prospective pilot clinical trial will be to assess the feasibility and acceptability of prolonged fasting for LC. The main questions aims to answers are;

  1. Does in-home prolonged fasting (7 days) is feasible and acceptable for patients with LC
  2. Is there a clinical benefit associated with fasting is LC patients

Participants (adults 18 year and older) will be asked to

  1. Fast for 7 days
  2. Have in-person visit at baseline (day 0) and at day 9 for checkups and tests
  3. Answer difference questionnnaires about their perceived health during and after fasting

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Actual)

25

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

  • Canada
    • Quebec
      • Sherbrooke, Quebec, Canada
        • Centre de recherche du CIUSSSE-CHUS

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

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Age 18-64 years
  • Diagnosis Long Covid based on WHO criteria (post-acute COVID-19 symptoms persisting ≥12 weeks) and validiated by an experienced cinician
  • Normal body Mass Index (18.5 to 39 kg/m2)
  • Able to communicate in and comprehend English and/or French language
  • Present written / signed declaration of consent
  • Ability to understand the patient information and willingness to sign the consent form
  • Willing to limit physical activity during prolonged fasting

Exclusion Criteria:

  • Current underweight condition (body mass index less than 18.5 kg/m2) or weight loss exceeding 3 kg within the last month or 5 kg within the last three months.
  • Current or history of eating disorder (e.g., anorexia, bulimia).
  • Psychiatric condition that limits understanding of the examination protocol (unable to consent)
  • Participation in another intervention study.
  • Fasting during the last six months
  • Pregnancy or breastfeeding status.
  • Diagnosis of chronic inflammatory bowel diseases, celiac disease or colorectal cancer according to the guidelines of the Canadian Society of Gastroenterology
  • Use of anti-psychotic drugs
  • Start of novel drug therapy for long COVID
  • Contraindication for additional blood draws (e.g. hemoglobin <100)
  • Taking opioid analgesics or undergoing treatment for opioid addiction
  • Opioid dependence or withdrawal syndrome
  • Type 1 or 2 Diabetes, or history of hypoglycemia
  • Active cancer
  • Baseline E+ (Na, K, Mg, phosphate) within normal range
  • Baseline ALT < 60
  • Baseline Hb > 100
  • Baseline INR within normal range
  • Baseline DFG < 50

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: Other
  • Allocation: N/A
  • Interventional Model: Single Group Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Fasting arm
Participants will be allowed to continue their regular drug treatment
Other: prolonged fasting
Participants will be fasting for 7 days

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Feasibility and Acceptability
Time Frame: From baseline (day 0) to end of follow up day 30
Retention rates will be used to measure feasibility and response to Likert-like questions for measuring acceptability
From baseline (day 0) to end of follow up day 30

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Mean changes from baseline to one month post-fasting on the SF 36 physical component score questionnaire
Time Frame: From baseline (day 0) to the end of follow up at day 30
The SF 36 questionnaire is a validated scale for assessment and monitoring of patients with LC. The 36-item scale includes 8 subscales : role functioning-physical, body pain, general health, vitality, social functioning, role functioning-emotional, and mental health.
From baseline (day 0) to the end of follow up at day 30

Other Outcome Measures

Outcome Measure
Measure Description
Time Frame
Fatigue severity score (FSS)
Time Frame: From baseline (day 0) to end of follow up at day 30
The Fatigue severity scale (FSS) (0-7 score, 7 being worse) is one of the tool to assess the severity of fatigue. It is validated for LC patients
From baseline (day 0) to end of follow up at day 30
Cognitive failure questinonaire
Time Frame: From baseline (day 0) to end of follow up (day 30)
Assess cognitive impairment (25 questions, 0-100 score).Higher scores indicat increased propensity to cognitive impairment and it is validated for LC
From baseline (day 0) to end of follow up (day 30)

Collaborators and Investigators

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

Sponsor

Université de Sherbrooke

Collaborators

Centre de recherche du CHU de Sherbrooke

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)

May 1, 2025

Primary Completion (Actual)

November 1, 2025

Study Completion (Actual)

December 1, 2025

Study Registration Dates

First Submitted

February 10, 2026

First Submitted That Met QC Criteria

February 10, 2026

First Posted (Actual)

February 18, 2026

Study Record Updates

Last Update Posted (Actual)

February 18, 2026

Last Update Submitted That Met QC Criteria

February 10, 2026

Last Verified

February 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • PF study
  • Programme PAFI 2024-2025 (Other Identifier: Centre de recherche du CIUSSSE-CHUS)

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

IPD Plan Description

Except for the study protocol that we are willing to share, personal and confidential will not be shared

Study Data/Documents

  1. Study Protocol
    Information comments: christine.rioux-perreault.ciussse-chus@ssss.gouv.qc.ca

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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