One of the greatest pieces of advice I can give is often met with the greatest resistance: stop feeding your cat dry kibble. I guess I shouldn't be surprised because I know what diet is best for me, yet I continue to eat things that aren't (sugars, etc.) The kibble complaints range from "it's convenient" to "my cat loves it". Eating at Burger King drive through is convenient, but not necessarily good for you (unless you try one of the amazing Impossible Burgers!) and I love Macaroni and Cheese but if I ate it every day, I would have a nutritional deficiency. The same is true for your cat, and to a greater degree because he is an obligate carnivore.
I advise NO DRY FOOD for your cat. The cheapest, nastiest canned food is 1000+ times better for your cat, over the most expensive dry food. And if you can afford to, raw food is the best thing you can feed your cat.
Here are some reasons to boot the kibble:
Dry food (kibble) is extremely high in soluble carbohydrates; higher than anything animals ever ate throughout evolution = it is not natural.
Your cat's biology is not designed to digest soluble carbohydrates.
Kibble can contain between 28 and 45% soluble carbs which promotes the wrong bacteria in the gut, compromises immune capability and may lead to allergies.
When you feed your cat a kibble diet, it creates constant blood sugar spikes due to the excessive carbs.
Simply said, feeding a mostly dry food diet will reduce the lifespan of your cat.
I've fed a variety of commercial and homemade raw foods to my cats over the years but the best brand I've found is Vital Essentials. Due to the fact that Vital Essentials entrees do not contain any fruits, vegetables, or grains; there is less than 1% carbohydrate content. This small amount of carbohydrates is naturally occurring from animal tissues and thus digestible by your cat.
Watch for the Kibble Conundrum series to continue with more information about cat nutrition.