We have 4 cats. 1 has about the combined weight of the other 3. So a diet is a must.

However we want our 3 “normal” cats to be able to eat whenever they want so I've built a simple box that's only accessible for cats with a, let's say, “normal” width. :)

I just bought a transparent plastic storage box (100l) for 10eur at Action and cut a hole in it. To avoid sharp edges as these boxes tend to shatter a bit I designed and printed these covers.

Instructions:

• Cut a hole in the box of 10cm wide, 14cm high.
• Depending on how much the box shatters, print a narrow, or wide cover (or both). You can also scale as needed.
• Slide the cover over the edges
• Give your normal cats a bit of time to adapt to the new situation.

I've added a picture of our unamused fat cat as proof that the solution works :D