Recruiting

Fasting & Immunity

Sponsor:

Cornell University

Code:

NCT07527208

Conditions

Fasting

Eligibility Criteria

Sex: All

Age: 18 - 40

Healthy Volunteers: Accepted

Interventions

Fasting

Study Details

Brief summary:

During fasting, the body shifts from using carbohydrates to relying more on fat as its main source of energy. This process is known as the 'metabolic shift'. Fat tissue helps supply this energy by breaking down stored fat into fatty acids, which are released into the bloodstream and transported to organs throughout the body. In addition to fatty acids, many other substances in the blood (such as metabolites) change during fasting to help maintain normal body function.

Immune cells also circulate in the blood and play an important role in protecting the body against infections and diseases such as cancer. However, it is not yet well understood how the metabolic shift during fasting affects immune cell function. The purpose of this study is to investigate how 24 hours of fasting influences immune cell metabolism and function.

Conditions

Fasting

Study ID

NCT07527208

Start date

Jun 1, 2026

Status verified date

Apr, 2026

Completion date

Dec, 2026

Anticipated

Primary completion date

Aug 28, 2026

Anticipated

Eligibility Criteria

Eligibility Criteria

Sex: All

Age: 18 - 40

Healthy Volunteers: Accepted

Inclusion Criteria:

  • Apparently healthy
  • Age 18-40y at the time of recruitment
  • BMI ≥ 18.5 and ≤ 24.9 kg/m2
  • Willing to participate in all study activities during the 3-day intervention
  • Signed informed consent

Exclusion Criteria:

  • Diagnosed with any chronic medical condition that can interfere with the study outcome (e.g., cardiovascular disease, cancer, diabetes mellitus type 1 or 2, liver disease, pulmonary disease, renal disease, inflammatory bowel disease, thyroid disease, long COVID, PASC)
  • Bleeding disorder (e.g., Hemophilia A/B, Von Willebrand Disease, or low platelets), current anemia or current use of blood thinners or anticoagulants (e.g. warfarin, heparin)
  • Any acute or chronic infection disease or fever in the past month
  • Antibiotic use in the past 2 months
  • Use of any prescribed medications (incl. GLP-1 agonists), except for contraceptives
  • Usage of recreational drugs in the last three months
  • Unstable body weight (weight gain or loss >5% of total BW in the past three months)
  • Following any restrictive diet within one month of starting the study (for example a ketogenic diet or weight loss diet)
  • Fasted for 16 hours or longer in the past week
  • History of an eating disorder (e.g., anorexia nervosa, bulimia nervosa, or binge eating disorder)
  • Allergic to one or more components of the standardized meal and/or shake (i.e., milk, wheat, and soy)
  • Average alcohol intake that exceeds 1 consumption/day or 7 consumptions/week over the past month
  • Tobacco smoker or regular use of nicotine products
  • Donated or intend to donate blood from 2 months before the study until the end of the study
  • Being pregnant or lactating
  • Participation in another biomedical study during this study

Study Design

Enrollment

28 participants

Anticipated

Intervention Model

Single group

Primary purpose

Basic Science

Interventions and Outcome Measures

Arms

experimental: Fasting

26-hour fasting

Interventions

Fasting

After consumption of a standardized breakfast (energy content adjusted to individual BMR), participants will undergo a 26-hour fast (water only), followed by consumption of a second standardized breakfast.

Primary outcome measure

  • Change in PBMC energy metabolism. [ Time Frame: Baseline, 24 hours ]
  • Change in activated PBMC energy metabolism. [ Time Frame: Baseline, 24 hours ]
  • Change in inflammatory capacity of activated PBMCs. [ Time Frame: Baseline, 24 hours ]
  • Change in PBMC subset abundance. [ Time Frame: Baseline, 24 hours ]

Central Contacts and Locations

Central contacts

Larissa van der Zon, MS

607-255-4045meta-shift@cornell.edu

Locations

Human Metabolic Research Unit, Division of Nutritional Sciences. Cornell University

Recruiting

Ithaca, New York, United States, 14853

Contacts

Sander Kersten, Ph.D.

607-255-8001dnsdirector@cornell.edu

More Information

Sponsor

Cornell University

Last update posted

May 7, 2026

Last verified

Apr, 2026

Keywords

  • Fasting
  • PBMC
  • Adipose tissue
  • Energy metabolism

Trial information was received from ClinicalTrials.gov and was last updated on 2026-09-10. This information was provided to ClinicalTrials.gov by Cornell University on 2026-05-07.