Hi Dumping. If you check out a few of these threads you will soon realise that there are very nearly as many theories as there are people on 5:2, Some read serious scientific papers and try to follow them, some of us keep it simple. As you get into it you will come to your own conclusions. The one thing I think most of us agree on is “whatever works for you” For a newbie I suggest you keep it simple. Use the box top right on your screen to find your TDEE (daily fuel requirement) and try not to exceed it on the five days. On the two fasting days keep it down to your set level. There are many thoughts on what you should eat on those two days, but as long as it is a healthy mix without too much sugar you will lose weight. Some people find that doing all of your eating in a limited time period , say 9-10 hours helps. I am new to that theory, which I am now adding to my basic 5:2 – it seems to work.