I think Nicole is trying to sneak this bump under the radar by not talking about it. Either she thinks we're dumb or that we're not paying attention. Based on the attention paid to Crazy Tom Cruise I don't know how she thinks we'd let it slide.
The alternative, of course, is that she's putting weight on in preparation for her super-secret hush-hush Aussie wedding, which makes perfect sense. Brides always binge before the big day, right? Right? Don't they?