Table 2 Patient perspective on iFIRE-C study assessments

Gradual increase of fasting period

• Thoughts on how adherence might depend on types of drinks or liquids that could be consumed during the fasting period.

• Appreciation for the gradual approach that allowed them to “mentally acclimate”

• Consideration for prospective participants’ work schedules (i.e., whether those who work night shift could still participate)

Commitment to 4 clinic visits

• Consensus about the amount being feasible

• Convenience was most salient code (e.g. convenience of clinic location relative to potential participants’ homes, convenience of available appointment times, and convenience for caregivers, as some may have to drive potential participants to appointments)

• Consensus that visits should be shorter than one hour

Biospecimens to be collected (blood, urine, and stool)

• Patients receptive to collecting samples at home, however one patient clarified that if they resided close to a clinic, it might be easier to drive there and receive clinic staff assistance with collection

• Consensus that collection is feasible if supplies and clear instructions are provided

• Some discomfort with stool collection, but not enough to prevent participation