First of all I must admit to laughing at what happened.

But my only advice is to just bite the bullet and put them on a feeding schedule. (I know, easier said than done) but they WILL get used to it.

Is Jack really TOO heavy to be healthy? If the answer is no, than maybe you can just keep things as they are

If the answer is yes, think of him and give scheduled feedings a try. Maybe you can offer DIET food all the time and the GOOD stuff at feeding times.