Boony.... Behave.

Have you searched through the forums? This comes up VERY frequently, and there're likely to be a number of threads on it...

People's bodies are different, of course, so there's no way to predict reliably what will happen to your wife unless she's been through something similar fairly recently.

That having been said, in general, fat is easier to acquire than to get rid of, for a variety of metabolic reasons. So, yeah, if she doesn't want to gain long-term, she's probably best off not doing so short-term, either.