If I were you, I'd drop the biscuits through the day between 3. Always one will eat most. What I would do is cut back 1/2 of the fresh, buy a 2nd food processor, because I'm squeamish. blitz it to slush, then add grated carrot/bit of apple, maybe a bit of broccoli, blitz again and divide the meals into 2 or 3, with 6? biscuits every 2nd day, to add a few minerals. Perhaps add water, so that the calories are the same, but the belly is fuller. When the weather is hot, you can do the trick with the 4 litre ice block, so they feel they are eating all day. (I say this feeding corn chips to my pet sheep, as I type...) But I would go to the butcher and get bones with almost nothing on them, to give to my baby and make her FEEL she is eating a lot.
PS My vet told me, for short term diets, to just feed pretty thinly covered bones, so they can chew all day