I'm 5'9" and weigh 132 lbs. My waist measures 30". I'm in the UK and dress sizes here are different from the US, but FWIW I seem to be somewhere between UK sizes 12 and 14 (US 10 and 12). According to the official size guides published many places, I should be a 14 UK with a 30" waist, but in practice most size 14 skirts and jeans are about 32-34" waist, and much too big for me in the hips as well. Mostly size 12 (10 US)is about right in pants and skirts, but I have to be careful, as I have seen size 12 clothes with a 26" waist, which I could never squeeze into. And then, I find that many size 12 dresses and tops are a bit narrow in the shoulders, and tight under the arms, so I tend to buy size 14 more often in those garments.
I am still dieting and trying to lose more weight, as I would like to get down to a 28" waist and wear size 10 UK (8 US). The only fat on my body is around the waist; if I eat too much carbs all the weight I gain goes right there. Nothing on the hips, butt or bust, where I would love to have it. So the only way to get a better figure is make the waist smaller, and I hate seeing fat there anyway. I am losing 2 lbs per week on my diet and exercise program, and staying fit and healthy; another month should get me there.
