I found this site on searching on information about fasting off/on while taking metformin. Although I take metformin for PCOS, yet I still take it, and the PCOS makes me pre-diabetic. So I need to lose weight, been trying to lose all the extra weight around the waistline. I could exercise for 3 to 4 hours, and still have the same weight. I'm tired and need to lose it now.