I am on my 8th week on ND. Was 15st 2lbs and am currently 12st 10lbs
You can read my postings and I recommend you also read "Peerless" as he started the week before me and has done great on his own version of the ND.
Like you, I followed the ND original diet rigidly, only eating non starchy veg.
I used "Astral nutrition" shakes as only 100 calories per shake so left me more calories for veg. Excellent shakes protein and nutrients wise. No supplements required.
The ND suggests no exercise while limiting to 800 calories a day and I would agree as anything strenuous I found to make me light headed. This last week I have done some light training only in an arpttempt to boost my metabolism to try and hit my goal of 12st 8lbs as I didn't lose any weight in week 7.
So, no banana if you are doing the ND strictly but lots of people have a version that isn't the original ND. So it's basically up to you.
Me? I wasn't sure about such things and decided best thing to do was to stick to what worked.
Good luck