I know what you mean. I often wish my girls could just tell me what's going on with them.

I found the calories for your specific kind of Friskies, and it has 182 for the can:
https://www.purina.ca/products/friskies-pate-chicken-dinner-cat-food/#feeding That is on the Instructions tab. About 20 calories per pound of ideal body weight is supposed to be about right for the 'average' cat.
You want to keep carbs under 10%... really, lower than that is usually best for a diabetic. Catinfo.org has a lot of info on feline nutrition, if you want to check it out. I have a link in my signature to the database version of the cat food list Chris gave you a link to. I find it easier to use since you can filter by your desired criteria. (If food options are different in Canada, maybe one of our Canadian members can offer you some assistance.) Dry foods are usually too high in carbs. It is best to get rid of the dry food completely, but if you want to keep using it, you may want to consider lower carb options. Dr. Elsey's Clean Protein Chicken has 4-5% carbs, and Young Again Zero has only trace carbs (though it has been known to cause runny, stinky poop issues).
Sometimes a little plain pumpkin added to food will help with constipation. Miralax is fine to give as well.