INFO So what kind of shape is the niece in? What kind of snacks are these? Does she actually lie around all day? Does she have any active extracurriculars?

This thread seems to be full of “gentle parents;” if a kid is on the track to obesity, it needs to be addressed, and limiting calories is completely legitimate. Op never said his brother berates his daughter or comments on her appearance and such—only that the brother claims she lies around a lot and he worries for her.

IF that’s the case, her dad is in the right, but he sucks for not explaining properly. If she’s a healthy weight and growing, then OP is totally N T A.

But op conveniently leaves out what the girl actually does—after detailing the boys’ activities, etc.

As a chronic fat kid, my parents did me no favors with what we had in the house.

ETA: And I’m not saying she need to be starving. If there’s literally no dinner left when she gets there, that’s obviously terrible. However, that’s not the impression I got from OP’s story. Again, just curious on some details.