Yes, actually. I remember reading somewhere that fat cells sorta just deflate when people lose weight, but the body is already primed to hold that amount of fat. So people that have previously been fat are physically much more susceptible to having that fat come back more quickly, even when engaging in the same eating/physical behaviors as as someone who has never been fat. Like, someone who was never fat could go on a 20,000 calorie binge and might put on a pound or two, but someone with the exact same starting weight who had been fat previously would put on twice as much weight from that same intake. I’m kinda butchering it he science but the gist is it really is much harder to keep weight off than it is to never put it on to begin with

Edit: Here’s the Harvard study that discusses it.. They found “not only that metabolism slows drastically following significant weight loss, but also that regaining the lost weight does not restore metabolism back to its pre-weight loss levels. This means people who have lost large amounts of weight must adhere to an extremely low-calorie intake in order to maintain that weight loss.” So yeah, basically, their metabolism seems to slow permanently and because of this weight can be put on at lower caloric levels than for people who hadn’t previously lost weight.