First sneaking food and lying about it

My daughter is 11 and has the opposite problem. She has to guard her lunch because the kids were swiping her food when she would look away. She is a pretty strong headed person and point blank tells them that she could go low and pass out if they take her food.

She takes a pretty healthy lunch and usually also has a treat or Cheetos in there that others really want. I told her if they didn't quit I could come explain to the class why they can't do that. Apparently they have stopped.