I never heard of those. Interesting!

For feline friends who are getting too plump, I would recommend something that works for humans too. ~~~Exercise.~~~ :) Since there is no such thing as going to the gym for cats, just spend a little time each day playing "stringy-snake" with them (old shoestrings tied together work fine for my kitties), or splurge on a packet of those little furry mousies they all seem to love so well, sprinkle liberally with catnip, and then it's playtime! Sometimes I think cats eat because they are bored. New toys and more fun might help to keep them away from the supper dish.