I don't know. Personally, I put on my weight in only 3 months. I went 150 to 300 because I became a shut in and literally ate all day to suppress my emotions. Even 10 years later I haven't lost it all. I'd lost 100, then got pregnant, lost most of the baby weight and had to have brain surgery. Only now am I healthy enough to start really working out and have started loosing again.
But even at my largest I was nowhere near that big.
I did the same thing. I moved with my boyfriend close to where my mom is and I have a much better support system to work out now. I'm a lot more motivated. I stress ate in high school and stopped doing sports and put on a lot of weight, and that was over the course of about 3 or 4 years. But I could never imagine letting myself get to that point.
But even at my largest I was nowhere near that big.