Dr. Rosenberg demonstrates how to clicker train your cat.
Clicker training is a fun, positive and effective training technique, very suited for cats.
the concept is simple . . .

The sound of a "click" (or any distinctive sound) is paired with a treat.
The "click" can then be used to mark specific points in time that coincide with the trick or behaviour that you want to teach your cat, and your cat  thinks of the treat, so effectively gets the reward during the act of doing the trick.  You give the treat shortly afterwards.

Watch the video below for a demo . . .

Cornell Feline Health Center "How To" videos:
Cornell Videos on Diseases:
Pet food websites:
Carb contents list of canned food:  look at both the old and new canned food list and also the non-US list for some additional Canadian foods.  Be aware that some foods will have higher quality ingredients than other foods.