Well I've seen that greens can be given in quantities of 2-4 cups per day, so 1-2 leaves isn't much. I agree with Lake Condo that 1 1/2" slice of carrot per day is quite a bit of sugar. The recommended 1-2 Tbsp/day of "treats" would include carrots and fruit total. So if a couple apple slices are given in one day, that should be their treat quota for the day, meaning no carrots in addition. Maybe alternating the carrots and apples would be an idea.
I've also heard parsley is to be limited. Ideally a wide variety of mixed greens would be served daily. I don't have the means for that, so I try to alternate instead. I'll get romaine and red-leaf lettuce or wrinkle leaf lettuce, and then offer one type per day. Maybe I'll give them romaine a couple days in a row, then basil from the garden one day, then a different type of lettuce the next couple days.
They don't always get a treat every day.