Keynotes enlarge in iBook

Hi all,

I have just come across a bizar phenomena.

I am writing my 5th iBook with iBooks Author as a training publication. It is paramount we keep the .ibook file as small as possible due bandwith and download restrictions. The iBook consists of one chapter with 21 pages with some pictures (compressed) but no movies. When I export the file to an .ibook file, the total size is 4,7mb, great.

Now I wanted to embed two keynote presentations into the iBook. The two keynotes alone are 4,8mb and 1,6mb, you would say the iBook would now be around 11,1mb...nope it's become a whooping 44mb?! To check if it was something with the template which I created myself I started from scratch using a standard Apple template, created 21 pages, randomly dropped in the same pictures and the keynotes, this time 41mb. (probably because it is missing the text)

I have embeddin the keynote into the iBook using the standard widget.

Any thoughts please? Thanks