The mechanisms by which released FAs promote insulin secretion is likely through the sensing of FAs by GPR40 receptor found on the surface of beta cells (153)
So the two papers above are doing real scientific work
Search terms like "vitamin B12 GLP-1 agonist," "cyanocobalamin absorption gastric emptying," and "B12 deficiency obesity surgery" yield relevant papers
Chronic fatigue, irregular sleep, mood swings, cognitive decline, are nerve issues all symptoms of B-12 deficiency
Insulin resistance and increased pancreatic beta-cell proliferation in mice expressing a mutant insulin receptor (P1195L)
Several factors may influence the degree and severity of insulin resistance, one of them being the amount of regular physical exercise