Hi Shelley,

The first thing I’ll say is buy and read the book.

The original 5:2 suggests no more than 500 calories for women on fast days (FDs) no matter what your TDEE is. There is no magic involved 5:2 works in the same way as any other diet as it creates a calorie deficit so we use up fat cells for energy ie the less you eat the more you lose.
Some people find it easier not to eat anything on FDs.

We get a large proportion of the water we need from our food so you need to drink plenty on FDs.
Hunger comes and goes in waves and when you feel it on a FD, have a glass of water and keep busy, it’ll pass.
You might feel a little light headed or nauseous. I’ve always found a pinch of salt and a glass of water get rid of it.

5:2 works. Weight loss isn’t linear, you’ll lose a fair amount the first week and then it’ll settle down. Some weeks you’ll lose nothing but do not despair just keep going.

Good luck.