Sizes are definitely larger because I work at Banana Republic and there was a time when a 16 from there was cut tight. I've only lost about 15 pounds since before Atkins and now the 12's are lose. The pricier and more expensive the garment, the more giving it usually is in the cut. I agree with the comment that Juniors and Misses are different. There are girls at Banana complaining about how the size 0's are too big now. It makes me mad (grr).
ALso remember "STRETCH", whoever came up with this concept is a genius. They put it in almost evrything now. I remember growing up and pants were just wool, or cotton, or whatever. Rarely did you find strecth material, especially in jeans. Even the stuff that's not supposed to be stretch has a little stretch in it. The clothes nowadays are being made differently.