How do you talk to a family member about their (possible) eating disorder?

I think my mom has a binge eating problem.

She has steadily gained ~25 pounds over the past year and a half after a year long stint of working really hard on making her diet healthier and exercising.

She will buy my sister a bag of those powdered sugar covered mini donuts for breakfast and then eat more than half the bag herself that night, then proceed to hide the empty bag. I’ve also noticed how she will eat an entire bag of popcorn or bag of chips or half a gallon of ice cream in one sitting…

The only thing that makes me not think its a ED is that everytime she eats all this food, she is mindlessly reading a book so I’m not sure she realizes she’s doing it.

Regardless, I’m worried about her and her health; How do I talk to her about this (as her 21 year old daughter)?

Any input or help I would appreciate more than you can know!