I believe in Canada, you can only fly with insulin-dependant diabetes if you meet certain control criteria,
and only for a Class 1 medical restricted to "as or with co-pilot"
For Class 3s, (i.e. private pilots), you tear up your license if you have insulin-dependent diabetes. A class 4 (glider/ultralight) may be possible.
Lots of information here:
http://www.tc.gc.ca/CivilAviation/Ca...betes/menu.htm