INS and type 2 diabetes mellitus: A case of repeated prolonged fasting (11–20 days) in type 2 diabetes patient demonstrated enhanced insulin sensitivity, with insulin decreasing from 14 to 4 mIU/L and HOMA-IR from 3.6 to 0.9 during fasting (overall 4.7 to 2.6), alongside glucose reductions and gut microbiota shifts resilient post-refeed [143].