I give up....

I'm tired of trying to get Kynzi not to eat SO much junk food! How can I do that when the other kids come over and eat ice cream at 11 at night????
It's not right! I said something and all I got was "well they haven't had any junk food all day". Yeah, so ya'll come over after 10p.m. and the kids get to eat ice cream this late at night? THAT'S NOT RIGHT! That's not respecting my rules for my daughter and when they get the junk food, then I'm stuck dealing with a temper-tantrum-throwing-3-year-old!
I'm sorry for the rant, but it upsets me that they do this every time they come over. It's not right to me or my daughter and I'm fixing to start stepping on some toes VERY soon. I'm tired of all the fit throwing I'm having to go through!
***EDIT***
The kids were bouncing the dang basketball in the house and I asked them to stop and they did. I was the only one that EVEN said anything to them about it....so now I'm listening to "Momma" "Mooommmmaaaa" because of them being loud! GGGGGRRRRRRRRRRRR!!!!!