I have the same problem. Max has always loved Readigrass and I was giving it to him in unlimited quantities until I joined this forum and realised it should be rationed . He now has it as a treat and we had a little evening ritual where he would run up his ladder into his balcony area and I would give him a pinch of Readigrass. He is not so bothered now he has 2 females to keep him company. Their new evening ritual is me hand feeding them Timothy Hay . I weighed them all this evening and Max has lost a bit of weight.
and, as for fresh grass, they're not out on it yet but I hand pick a bit occasionally. I have to inspect the lawn very carefully for deposits local cats may have left.
This is why this forum is so good. Cannot beat advice from people in the know!