I don’t have a link (I’m very sorry) but there are feeders that you can get that have a tag that you can put on your grazer’s collar. The feeder only opens when it senses the tag. I think it can work with microchips in the cat too.
Edit: found it :) here’s the link https://www.amazon.com/OurPets-WonderBowl-Selective-Pet-Feeder/dp/B00C1BYETO/ref=mp_s_a_1_7?adgrpid=55870052317&gclid=CjwKCAiAlajvBRB_EiwA4vAqiBgZPYf3gJTm0qFNnlck4BCNpsoKdrsMfAnjpYQSiJSo8Tg0BdwxUxoCgJIQAvD_BwE&hvadid=274742875576&hvdev...
Aside from what's already been suggested. I have been really intrigued by the idea of selective feeder bowls for pets. I have not tried them myself as my pets are meal fed and nobody leaves any behind to steal, but they sound nice in theory!
I think there are probably other brands/versions out by now but here is an example: Selective Feeder Bowl
Like a lot of people are saying, timed meals worked wonders. However I had the same problem because my partner and I work odd hours (so we couldn't regularly put down the meals ourselves).
There are some really cool automatic feeders that use chips to keep the cats out of the food. The one I chose wireless whiskers. It's pricey but I liked some of the features that this one had (one bowl for multiple cats, auto-diet, and a large gravity feeder). I've had mine for over a year and it's been working great to keep my chubster from gaining weight.
There was another one that was pretty decent looking as well called the wonderfeeder. If you got two you could be sure to monitor each kitty's diet.
Hope that those help you!
Not a vet, but have you looked into something like this?
http://www.amazon.com/OurPets-WonderBowl-Selective-Pet-Feeder/dp/B00C1BYETO
Sorry if this doesn't help you. I think it is a good idea though