Intermittent Fasting and a No-Sugar Diet for Long COVID Symptoms

NCT06214455 | Completed Results

• 1 other identifier: 2022-06-PNWU
• Study Type: interventional
• Target: 77
• Locations: 1 country
• Sites: 2

Brief Summary

This cross-over study will assess a no added sugar diet, a restricted daily eating window, and one or two full day water fasts to determine if there is an effect on self-reported symptoms of Long Covid (PASC).

Conditions

Long Covid19; Long COVID

Keywords

COVID-19; fasting; diet

Outcome Measures

Primary Outcomes (2)

• Change in LC-Score, Per Treatment

  This Outcome Measure is calculated by subtracting the Long COVID symptom severity score (LC-Score) before a treatment from the LC-Score after the treatment (i.e., score-after minus score-before). Negative values represent a reduction in number and severity of symptoms following treatment. LC-Scores are the sum of severity scores (0-4) for 28 common symptoms plus the count of 32 additional symptoms present. The maximum possible LC-Score is (28x4)+32 = 144.

  Before and after 4 weeks of Fasting treatment or TRE treatment

• Change in Number of Long COVID Symptoms, Per Treatment

  This Outcome Measure is calculated by subtracting the Number of Long COVID symptoms (numLCsym) before a treatment from the numLCsym after the treatment (i.e., number-after minus number-before). Negative values represent a reduction in number of symptoms following treatment. The numLCsym is the count of 60 common symptoms.

  Before and after 4 weeks of Fasting treatment or TRE treatment

Secondary Outcomes (3)

• Change in LC-Score, Overall

  From enrollment to the end of the final treatment (10 weeks)

• Change in Number of Long COVID Symptoms, Overall

  From enrollment to the end of the final treatment (10 weeks)

• Serious Adverse Events

  During 4 weeks of Fasting treatment or during 6 weeks of TRE

Study Arms (2)

10-12 hour daily Time-Restricted Eating (4 weeks)

ACTIVE COMPARATOR

In this crossover trial, half the participants did the 10-hour TRE first (treatment A), half did it last. A no added sugar diet was suggested for the entire study.

Other: Low sugar diet and 10-12 hour eating window

8-hour TRE, weekly 23 to 60 hour fast (4 weeks)

EXPERIMENTAL

Eating in an 8-hour window daily, with one 23-60 hour fast per week. A no-added sugar diet was suggested.

Other: Low sugar diet, 8 hour eating window and fasting

Interventions

Low sugar diet and 10-12 hour eating window OTHER

Low sugar diet and 10-12 hour eating window for four weeks

10-12 hour daily Time-Restricted Eating (4 weeks)

Low sugar diet, 8 hour eating window and fasting OTHER

Low sugar diet, 8 hour eating window and a 36-60 hour fast once per week for four weeks.

8-hour TRE, weekly 23 to 60 hour fast (4 weeks)

Eligibility Criteria

• Age: 19 Years - 69 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Adult (18-69 years old)
• Five or more common Long Covid symptoms
• Free from fever \> 100F and known bacterial and parasitic infections
• Must indicate willingness to limit certain supplements and report all medications.
• Must indicate willingness to make significant dietary changes - and limit daily eating to an 8 or 10 hour window.
• Must indicate willingness to attempt 36 hr or 60 hr water fasts each week for 4 weeks.
• Have a valid email address and phone number
• Reside in the United States
• Be able to read and to communicate in English
• Must indicate willingness to avoid "extra" supplements such as Fish Yes Oil, Cod liver Oil, Krill Oil, MCT oil, Coconut Oil, Tumeric/Curcumin, Berberine, Quercetin (\> 500 mg), Red Yeast Rice, French Marine Bark extract, Red Sage, Ginko biloba, Oregano Oil, Peppermint Oil, Black seed oil, Cinnamon bark extract, Elderberry, Stinging Nettle, Milk Thistle, Monolaurin, Vendicinals 9, Tollovid, QuadraMune and all Probiotics.
• Must indicate willingness to avoid certain nutraceuticals such as Zinc (more than 25 mg), Arginine, Glutamine, Palmitoylethanolamide (PEA), Alpha Lipoic Acid, L Carnitine and Taurine during the study period.
• Must indicate willingness to avoid longevity supplements such as NAD+, Niacin, NMN, Nicotinamide Riboside, Spermidine and Fisetin during the study period.
• Must indicate willingness to halt Olive oil consumption greater than 1 tsp daily during the study period.

You may not qualify if:

• Likely COVID-19 or SARS-CoV-2 infection \< 45 days before enrollment
• Body Mass Index (BMI) must be 20 or greater
• Past history of an eating disorder.
• Previously fasted more than 18 hours with Long COVID
• Currently doing intermittent fasting
• Pregnant or breast-feeding
• Severe pulmonary disease requiring supplemental oxygen
• Partial loss of vision due to macular degeneration
• Any recent (90 days) history of malignancies, fractures, surgery, radiation, chemo, anesthesia, or traumas
• Diagnosed with Type I or Type II Diabetes
• Previous Autoimmune condition
• Heart condition (Coronary artery disease, Heart valve disease, Heart No failure, Stroke)
• Pre-pandemic Arrythmia
• Liver disease
• Previous Chronic Health Conditions that did not fully resolve (Includes ME/CFS, Lyme Disease, and Fibromyalgia)

Sponsors & Collaborators

• Pacific Northwest University of Health Sciences: lead

Study Sites (2)

Remote trial - anyone residing in the United States

Boulder, Colorado, 80303, United States

Location

Pacific Northwest University

Yakima, Washington, 98901, United States

Location

Related Publications (1)

• Bunker T, Horne BD, Baldwin MD, Sorrells R, Turner S, Laube L, Solomon A, Horne LA, Novack J. Intermittent fasting and a no-sugar diet for Long COVID symptoms: a randomized crossover trial. Sci Rep. 2025 Jul 29;15(1):27563. doi: 10.1038/s41598-025-07461-0.

  PMID: 40730806 RESULT

MeSH Terms

Conditions

Post-Acute COVID-19 Syndrome; COVID-19; Fasting

Condition Hierarchy (Ancestors)

Pneumonia, Viral; Pneumonia; Respiratory Tract Infections; Infections; Virus Diseases; Coronavirus Infections; Coronaviridae Infections; Nidovirales Infections; RNA Virus Infections; Lung Diseases; Respiratory Tract Diseases; Post-Infectious Disorders; Chronic Disease; Disease Attributes; Pathologic Processes; Pathological Conditions, Signs and Symptoms; Feeding Behavior; Behavior

Limitations and Caveats

Limitations include no follow-up symptom surveys after the intervention period to assess the durability of patient gains. This trial relied on patient-reported symptoms and severity assessment since there are no available biomarkers for Long COVID. Finally, although subjects were excluded if they had a prior chronic health condition, changes in other factors not related to the fasting interventions may have impacted participant symptoms, which could bias outcomes.

Results Point of Contact

• Title: Jeffery Novack
• Organization: Pacific Northwest University of Health Sciences

jnovack@pnu.edu

2063693967

Study Officials

• Jeffrey Novack, PhD

  Pacific Northwest University of Health Sciences

  PRINCIPAL INVESTIGATOR

Publication Agreements

• PI is Sponsor Employee: No
• Restrictive Agreement: No

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: SINGLE
• Who Masked: OUTCOMES ASSESSOR
• Purpose: TREATMENT
• Intervention Model: CROSSOVER
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Model Details: 2-week baseline period with adoption of no-sugar diet followed by treatment AB or treatment BA in a randomized crossover design.

Study Record Dates

• First Submitted: January 3, 2023
• First Posted: January 19, 2024
• Study Start: November 4, 2022
• Primary Completion: July 1, 2024
• Study Completion: September 10, 2024
• Last Updated: May 14, 2026
• Results First Posted: May 14, 2026

Record last verified: 2026-04

Data Sharing

• IPD Sharing: Will not share

Locations

US (2)