Looks nice. Definitely you've put great effort in this. As a feature request; I may have missed, but a chart option, showing calorie intake or blood glucose level would be great. Also a feature to enter weight would be nice as well.
Also I would suggest to mention some sort of disclaimer for insulin estimation feature.. because it depends a lot from patient to patient (ie- weight, age etc) and you may not want to give medical advice..
Nonetheless I like the app as a long time diabetic.
: Photo FX app for Android - yay! like there are not enough already...
Motorola MPX200 - HP hw6515 - Nokia N95 - HTC Hero - Samsung Galaxy S II
Tablet: iPad 1 - Google Nexus 7