I guess you mean Trying To Conceive? (Sorry for being thick, Google gives lots of other possibilities but this is the most plausible
.) Er, I'm not
I know that fasting is not recommended for pregnant mothers, I haven't heard (or if I have I have forgotten) any advice for those trying to get pregnant... The subject came up in a topic
here but in the context of losing weight as helping fertility (and helping to qualify for fertility treatment in UK).
I would have
thought that 5:2 would be fine for TTC and if if your weight is creating problems in this area then obviously losing the weight will help. Someone else might know more.