I have an answer for you (well, sort of). You see, my cats are on hunger strike. Kitty Crack (TM) - otherwise known as Royal Canin Sensible 33 - appears to have been discontinued. In its place is RC Sensitive (woo! English!) 30, which has anti-hairball and extra tooth and gum health properties as well as being formulated for delicate tummies. They hate it. Or change. Dunno. But they're not eating hardly at all!

However, we feed to schedule and usually (though not quite at this 2nd day of the strike) pick the food up again half an hour later. And the girls have weighed quantities of food (much less than the packet suggests: they were still putting on weight otherwise, and don't yell for more on what they get). Admittedly, they weren't anywhere near as tubby as either of yours, but Minna is now muxh more playful.