Exactly -- I recall Gaga starting to fatten up around the time that she was working with Dr. Luke.  Kesha says Dr. Luke called her a refrigerator (ha! so true), and Kelly Clarkson makes vague noises about him being "sleazy" and how he's "demeaning to women," so going by how she peaked at planet size just a few years later, I conclude that Clarkson's problem with Dr. Luke was that he was grossed out by having to have his best work reeeee'ed out by that ever-expanding, whinging fat ass.