150 Pound Woman Wears a Size 6 ?????

Here is something that has been bugging me for quite some time now. I am sure you have seen the TV and print ads for the various weight loss programs that are out there, and most of them are all hype with very little true weight loss success. I also read an article a couple of months ago that was in "People" magazine about how people lost half of their weight. I'm not sure why this bothers me so, but I just don't believe that someone who, say weighed 200 pounds and lost 50 pounds can say that they now are a "size 6" or a "size 4." I find that so unbelievable because I don't weigh anything like 15o pounds and I can't squeeze my body into a size 4, 6, or 8, sometimes not even a 10! Maybe some of the people are super tall, so that would make a difference, but I swear the article I read said these women weren't too different in stature than I am. I am not very tall--5'4''. I just don't get how someone who outweighs me by 20 or thirty pounds can wear such small sizes. I guess I'm just jealous, because I do weigh more now than I have in many, many years, and I am a far cry from over weight, but certainly don't wear a petite size 6. I would like to know where these gals buy their clothes, because where I live, a 6 is pretty darn small!