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OpenTrials
Completed

NCT Number: NCT06214455

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

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).

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Key information

Age range

19 year–69 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Remote trial - anyone residing in the United States, Boulder, Colorado, United States

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About this study

This remote study will use a cross-over design to test a diet change plus a 10-12 hour eating window (Treatment A) compared to a diet change, an 8-hour eating window, and one 36 or 60 hour fast per week (Treatment B). Both potential Treatment A and potential Treatment B are 4 weeks in duration. To be eligible, subjects must have a minimum of five common long COVID-19 symptoms. The fasting will limit food intake but not water intake. There will be a two-week run-in with weekly surveys of patient-reported symptoms and severity. The subjects will be randomly assigned to Group AB or to Group BA. Since the water fasts are at the beginning of the week (with symptoms surveyed at the end of the week) there is a 5-6 day washout and then a cross-over to the other treatment for Group BA. A Likert 0-4 scale is used to track the severity of 28 of the most common patient-reported symptoms each week. An additional 30 symptoms are also tracked. Subjects are asked to follow a no-added sugar diet for the entire 10 weeks of the study.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • 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.

Exclusion criteria

  • 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)
  • Prescription anticoagulation medication that cannot be halted during the study period. Brilinta (ticagrelor), Plavix (clopidogrel), Coumadin, Warfarin etc.
  • High Cholesterol medications that cannot be halted or reduced during the study period (Fenofibrate, Statins > 10 mg)
  • Anti-inflammatories or immunosuppressants such as Steroids, Low dose Naltrexone (LDN), Maraviroc, Remicade/Infliximab or Colchicine that cannot be halted during the study period
  • Metformin, Ivermectin, or peptides such as BCP-157 that cannot be halted during the study period

Treatment and study plan

Low sugar diet and 10-12 hour eating window

Other

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

Primary outcomes

  1. Change in LC-Score, Per Treatment

    Time frame: Before and after 4 weeks of Fasting treatment or TRE 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.

  2. Change in Number of Long COVID Symptoms, Per Treatment

    Time frame: Before and after 4 weeks of Fasting treatment or TRE 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.

Secondary outcomes

  1. Change in LC-Score, Overall

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

    This Outcome Measure is calculated by subtracting the Long COVID symptom severity score (LC-Score) at baseline from the LC-Score after the final 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.

  2. Change in Number of Long COVID Symptoms, Overall

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

    This Outcome Measure is calculated by subtracting the Number of Long COVID symptoms (numLCsym) at baseline from the numLCsym after the final 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.

  3. Serious Adverse Events

    Time frame: During 4 weeks of Fasting treatment or during 6 weeks of TRE

    Adverse events were medically reviewed and categorized as Serious if appropriate

Sponsors and collaborators

Lead sponsor

Pacific Northwest University of Health Sciences

Other

Registry information

Official study title

The Effect of a No-added Sugar Diet, Time-restricted Eating and Periodic Water Fasting on Long COVID Symptoms

Important dates

Study start
2022
Primary completion
2024
Study completion
2024
First posted
Jan 19, 2024
Registry last updated
May 14, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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