Sometimes nothing at all – depends on how it is going. When I do eat, it is mostly fruit. Not fashionable on these sites I know but it works for me. I will also permit myself a little pickled herring with salad. That works better than it sounds (or perhaps I think that because I have worked in Norway). My wife also 5:2s and she favours a hard boiled egg with her salad.

Welcome Amyb,
I started 7 weeks ago and I´m also aiming for losing 3 stones. I have already lost 1.2 stones so I´ve 1.8 stones to go. My method on FD is to eat nothing at breakfast, only drink green tea and one cup of coffee. At lunch I have a single bouillon in boiled water (just a 10 cal). Sometimes I have to add 2 boiled eggs at lunch if I´m really hungry (ca 150 cal). Then I have an early diner (around 6 o´clock) which is very light (chicken salad, salmon or similar). I want to press myself on FD in order to lose weight fast, because it fits my personality better to do things aggressively in a shorter period than to do it more slowly over a long period.
Best of luck to you.