No, it's not true that they will stuff themselves until they burst. Also pyramiding is related to the conditions in which they're kept, and diet is at best a small part of that.
I only feed mine once a day in the morning, There are 25 all told. So about half a romaine lettuce & some stalks of coriander or cucumber peelings etc etc . Even if I put out 3 times as much it would still disappear. So I will not kill them with kindness, which is a bad fault. BUT the only exception is to make sure that the babies have a good feed. at least 2 hours of chomping away, free from the older ones , who would scoff the lot before the babies could eat their fill.