Although that snake shows a fairly extreme example of "hips" (especially for a young adult), I have had a few that extreme. Although I have no reason to believe it is anything different, based on the photo, of course I can't be sure. But "hips" (fat deposits) is what I would call it. I do have a copy of a vet report from somebody who once had a snake that looked like that, so she took it to a vet and they actually did a biopsy, just to be sure. They found fat deposits. However, I would never discourage somebody from going to a HERP vet (not cat and dog vet) if they are really concerned. You know your snake better than anyone else does. But I would not be overly concerned if it was my snake.
When I have a snake showing hips, I still offer food once per week like I do for all adults. But instead of a jumbo mouse or a couple of weaned mice, I might offer only a hopper. And I try to give it a little exercise, although that is easier if you have only a few pets. I think the suggestions given for more exercise are on track. If your snake is genetically predisposed to this pattern of fat deposits, you will probably not get rid of it entirely, even if your snake loses a lot of weight. You probably know people who lost a lot of weight but still had "love handles" or who still complained about a big rear. However, you can probably diet and exercise her enough to keep her in good health and to lose part of excess fat in the rear third of her body.
