I would say just try to start up a casual conversation and get to know them a bit as a person. Any time food comes up in the conversation might be a place to start. I remember there was this girl I was into in high school. I'd been acquainted with her since 6th grade and she had always been slim, came from a slim family too. But on multiple occasions she talked about food in a way that perked my ears. Like how she enjoyed going to a restaurant with her friends and the fatty chicken wings were so delicious. The time I had my molars removed and couldn't eat much for a week, she said "Be sure to gorge yourself ahead of time with whatever you love to eat!" She also said, "You know how if we eat too much, the food rather becomes our poison?" And then she chose to read a book about a girl with anorexia for psychology class. In college she admitted to being lazy, hoarding way too much junk food, and just spending all day in the cafe studying and munching away. But she didn't feel ashamed of it. I could see that she'd gained a bit, but nothing that obvious. At that time I was super conflicted about it though and didn't have the guts to even bring it up with her! Darn.
7 months