How much to feed a 4.5 lb cat?

Kiran wrote:
Phil P. wrote:
: An average, healthy, adult, neutered, moderately active, indoor cat has a
: daily energy requirement (DER) of about 20 calories/lb (45 kcals)/day...

I have been going by weight-based recommendations on the cans and am
not fluent in this language. I was about to guess that a 4.5 lb cat
needs 20x4.5 = 90 calories, but I am not sure what 45 kcal/day means.

This could be too much. I just looked up Science Diet at
www.hillspet.com and they recommended 2! cans per day for a 5 pound
cat. That's 190 kilocalories! Offhand, they seems to be twice the
calories an indoor, neutered, inactive cat would need. I would get a
scale. A good scale is over $100. But I am thinking. A 10 pound postal
scale, with a tray on it, would be awkward, need a Hold button, but put
a tray on it, and the cat on the tray?

The weight recommendations from all the companies do not make sense to
me. They seem way too high. Sometimes. They need to be more specific.
Even Science Diet does not specify if the weight is for a target weight
or the present weight or what? A 10 pound cat aiming for 8 pounds is
not the same as a 12 pound cat aiming for 10 pounds. I pointed this out
to them and hope that in the future they will have far more accurate
information.

Take Phil P'.s recommendation of 30(BW) + 70 for example for relatively
small animals.
That's 30 x 2.04 [4.5 pounds / 2.2046 = 2.04 kg] + 70 = 131
calories/day
But if neutered, inactive, I might say 100 kilocalories per day, or 1
small can.
I think Phil P. said 30% less for inactive, neutered cats, which is
about this. But Science Diet says 1 1/2 cans to 2 cans per day. This is
too high for your particular cat in my highly uneducated opinion.

If you pester Science Diet, they will pull out the scientific
literature, which then specifies about 6 different levels of caloric
intake depending on any specific cat's situation! They really need to
put all 6 different levels on their food products so people don't make
the mistake of feeding indoor, neutered, and inactive cats what an
intact and active cat requires!!!

I'm not a vet and I don't have all that much experience except all the
information I am getting is not logically consistant from the
companies. That's not good.