Age

18–any

Sex

ALL

Healthy volunteers

Not accepted

Diagnosis of advanced esophageal, gastric, non-small cell lung cancer (NSCLC), HCC, cholangiocarcinoma, melanoma, RCC, or MSI-H cancer
* Planned treatment with ICI-based therapy
* ECOG 0-2
* Ability to provide informed consent
* Willingness to follow dietary guidance and record adherence
* BMI = 23-40

Diabetes requiring insulin
* Active eating disorders
* Sarcopenia and/or cachexia (mild, moderate, severe), including sarcopenic obesity
* A history of hypoglycemia, including idiopathic and postbariatric hypoglycemia
* Patients taking sulfonylureas (concern for hypoglycemia with fasting)
* Night shift workers (at discretion of investigator)
* \>10% weight loss within the past 3 months through self-reporting or chart review.
* Any uncontrolled autoimmune condition or recent high-dose steroid use
* Severe GI or endocrine disorders precluding fasting including but not limited to malabsorption syndromes, gastroparesis, or Addison's/Cushing's
* Pregnant or breastfeeding

Pilot Study of Intermittent Fasting With Immune Checkpoint Inhibitors