Calories in cat food

I know it is important for our diabetic kitties to have low carb food.
Since our kitty is also fluffy we need to limit or reduce his intake.
He is currently about 17+ pounds.
About 23 before being diagnosed with diabetes in January of this year.

We are now trying to feed him mostly IAMS Perfect Portion Chicken pate.
Getting rid of all kibble.

Does anyone know how many calories are in each portion of IAMS grain free Perfect Portions.
Not sure how many to give him each day.
I usually feed him 3-4 times each day.

Today I gave him 2 portions. One in the early morning about 5, and another about 7.
He was quite hungry today.
He licked the bowl clean.
I often give him more pate around noon, and again at supper, and leave
him out some pate to graze on at night.

I thought I read on the package that you are to give 3 portions for every 5 pounds of kitty.
Is there a formula to figure out calories in cat food as there is to figure out carbs. Don't want to overfeed him, but don't want to starve him either. Always has enjoyed his grub.

 

Looks like 46 cal per portion.
See here:
https://www.iams.com/cat-food/perfect-portions-healthy-adult-pate-chicken-tuna-12ct-mvmp

 

Gosh, I'm blind. I was on that site multiple times and didn't see it. Thanks for pointing it out.