Can I eat the leaves from my broccoli di ciccio?

I am growing broccoli di ciccio, an italian variety of broccoli that produces lots of leaves/ side shoots. I’ve read that the leaves are good to eat – but the question is, can I eat them before the plant produces the broccoli (right now I have lots of leaves but the broccoli hasn’t grown). I don’t want to inhibit the plant from producing broccoli and I have no idea whether harvesting the leaves now will cause any harm to the plant.