Look at female relatives. Some women tend to gain weight in the bottom portion of their body and can get smaller on the hips part. If her thighs touch, then she is likely to be able to also lessen the width of her hips when she losses weight (because in that case it is more likely that she stores fat in her thighs/hips).

Hips are bone, you can’t just shrink them. They can make a person look bigger/wider than they are in the bottom area. There are lots of skinny girls that have wide hips.