How do I get my fat cats to lose weight?

We have 2 cats, sisters from the same litter, now age 5. They’ve been getting steadily more corpulent over the years, one is now 15lbs, and the other – I just realized – is 21lbs. She’s almost as wide as she is tall!

The more robust kitty will eat and eat and eat, so we’ve always rationed their food. However, the holidays are not kind to them as we tend to leave for a couple of weeks in a row, and have friends check in on them every few days. In between checkins, to allow for some variance in when folks come by, they tend to get more than the usual amount of food.

So, now, here we are.

What should we do? We currently limit food – we could limit further; we could limit better (when we’re away); we could splurge on better diet food (higher meat content); we could find some means to exercise them (ideas here?) Something else, more or different?

[I should add that right now they are taking turns standing on my keyboard until i feed them.],