Hi Kath,
I didn't do the low fat/carb/calorie diet because I just didn't to want to deal with food. I did the cambridge diet instead, with Mr A's blessing of course. It suited me better not to mention that I had supplies of the stuff from an earlier time.
However, seeing as you have about 5 weeks to go, may I suggest you start eating along Slimming World's Red Day lines. More protein and veg and then gradually cut down portions as you head into the final 2 weeks before surgery. It will make the transition easier. If you've done slimming world you'll know what I mean. If not, check out the SW forum or buy a SW magazine. They usually have a 7 day sample menu for red & green days. I think slimming world's red days suit the low carb/fat diet Mr Ammori recommends.
There's no harm in starting on multi-vitamins at this stage too.
Hope that helps.
PS, is there no sample menu in the pre-op booklet?