Just like most things, instead of saying "no," just say that you can have some when we ... (think of the next opportunity that you would allow her to have some). And then add that it is not healthy to eat it everyday. Keep it short and simple.
Do the same for playing with something that is not appropriate at that time. Say that you can play with that when .... I think we say "no" way too often and then they just think it is a word that limits their fun instead of there being a reason like safety or health.
Sounds like you are doing a great job!