It's a fairly common 5:2 IF (if you google that you will find lots of info). Some people do multiple "meals" on the fast days but keep the overall calorie count low, like under 600. I prefer eating just the one meal and often go even lower. On Monday I had 345 calories. Here is something counterintuitive - I find it easier to fast after a light meal than after a heavy one. I avoid heavy meals; they seem to stoke the fires of the digestive system to want more fuel as soon as that meal has moved along out of the way.