Do the girls have access to enough food at home?
When I was a teenager, I was in a situation where I didn't always have access to food and when I got access to it, i binged and would steal food. I was never sure if there would not be another meal for a while. I was ashamed and would be picky with food in front of some people and hated people seeing me eat as I would just gorge and didn't understand how to eat normally. At some points I would be overweight as I had access to food at that time and couldn't stop the thought of not having food again.