Mesomorphs and endomorphs, take note: exercising with weights won't turn you into Twiggy, but you won't look like Arnold either. Valerie's story is a familiar one: bulging size 16 periods followed by starvation meals, weight loss, and a slow return to her former self. This time, however, the weight has not only stayed off but moved around becomingly; she's no skinny minnie, still needs some camouflage in clothes, and can't quite sculpt her calves and ankles as desired, but she now frequents 5-7-9 shops and feels great. Her system? Basic barbell equipment (a $65 investment) and a high-protein low-fat maintenance diet. ""There is no way you can do a more effective job in a short amount of time than by weight training,"" the Carnes maintain, and their exercises for specific body areas can be tailored to individual needs for local trimming--a claim doctors always dispute. They're kind of cavalier about popular diets (noting publisher Stuart's prodigious loss but not his subsequent gains) but don't pretend that weight exercising is all rather than part of a reducing plan. Not as shrewdly focused as Edelstein's The Woman Doctor's Diet for Women--more like a balanced long shot.