Cosmo, I think Karen was just pulling your leg.  Surely she was.

A 12-week old kitten will chew on just about anything and swallow it as
well.  As a cat owner, you need to be alerted to that reality.  From time to
time we get new ones in the house, and that means consciously picking up
(removing) all things that are an attractive nuisance to young cats.

In spite of our diligence, I have found the most interesting things in the
litter box; and one wonders how such objects made their way through the
serpentine concourse of the cat's innards.

Look at the kitten as a small child and take great care to remove as many
things as possible that a small child might pick up and put in its mouth.

Tags from clothing, the small wire/paper/plastic strips for tying bags,
loose pills, buttons, leaves --and yes, aluminum foil.

--Geno

Most of them don't.  I use it to keep my cats out of plants and
off counters too.  Kitten is teething, hunting, finding things to
do.  The insulation is really bad, need to find a way to keep
the kitten from getting to it.

Is it actually eating the foil or just tearing it up?  If "it" is actually
digesting it I would take the cat to the vet.  Not only to make
sure the stuff it's been eating hasn't harmed it but to check it's
blood.  Maybe the kitten is low on iron  <g>.  Kidding but animals
will eat wierd stuff trying to make up for some medical or dietary
problem.

If it's just gettting into stuff, now is the time to teach it was is
acceptable and what isn't.  Grab one of the zillions of kitten
toys you have probably bought and get the kitten playing
with it whenever you catch it trying to play with foil or knitting
needles or insulation etc..

AG

Usually they don't, but some cats seem to develop a taste for it. Try rocks
around your plants instead - they work for me. As for the insulation - it
may be dangerous, so try to keep your cat away from it. If possible, keep
your cat downstairs. Kittens are playful and will attack virtually anything
that moves, climb anywhere etc. You have to train your cat as to what is
acceptable/unacceptable behaviour. Try a water pistol/spray bottle as a
deterrent. Most kittens settle down with age, and can learn quite quickly -
though some stubborn cases may take a while. I do not normally advocate
striking a cat, but as a last resort with some biting cases, slapping the
cat on the top of the head with the flat of your hand (not too hard) with an
accompanying hiss or yell usually stops the most stubborn cases.
-Silver
"I love cats because I enjoy my home; & little by little, they become its
visible soul."

- Jean Cocteau 1889-1963.