Lycanthrope, don't give the woman false hopes of reducing her size. Exercise and diet might sound like a reasonable proposition (as opposed to suggesting a fad diet), but the most likely outcome of an attempt to reduce size is a short term reduction followed by gaining more weight that was lost in the first place, so the long term outcome of most attempts to lose weight is weight gain. Fewer than 5 % of people succeed in LONG TERM weight loss. Normally, one does not embark on a venture with such pitiful odds.

exercise for the sake of performance, feeling good, improving cognitive abilities, and what have you is a good idea, though, as is the advice to gain confidence, etc., but no, attempting to lose weight for a person already unhappy about her size is really, really a losing proposition, meaning that OP won't lose weight but will lose what precious little confidence she currently has, and then what will she be left with - frustrated, defeated, and disappointed?