Be sure to read your treat labels too! Often giving your cat treats is like feeding your kids Snickers Bars - not at all healthy. You can be feeding your cat a nutritious meal and then undo all that good with a handful of high carb rewards. I always look for food and treat products with very simple, and few/limited ingredients. The PureBites is one of my favorites to train and reward with; it has one simple ingredient "chicken breast". The moisuture content is low (due to the freeze-dried process) so you wouldn't want to feed this as a meal without hydrating it. (But this manufacturer makes meals along the same lines with higher moisture content.)
And remember - the kcals from treats should be considered in your cat's overall daily kcal intake.