I agree it was kinda weird and misplaced.

Teen and especially preteen girls tend to be really skinny until they put on their adult fat. I remember fitting into a size 0 at 12 and 14, same with my sister, we were both healthy.

Then I looked at my yearbook about last year and I notice something, many girls were very very skinny, just like I was at that age. Many seemed to have the same kind of body. They didn't have the more adult body I (and many others I'm sure) grew into. In an unrelated conversation I had with a friend, she was mentioning about how her body has changed since she was in high school.

You can't really compare a child with an adult.

I like small details when reading stories. Even if unimportant, it's fine to put it there.

I agree, I'm not sure what relevance the girl's weight had to the paragraph.

The author says they were in the snack aisle and she was "begging for cookies". I read the reference to her weight as a clumsy way of implying that the girl's parents were giving in to her demands instead of teaching her what the snacks cost.

As a hook for the article I thought it was clumsy and unnecessary.

It's even more odd juxtaposed with the "a blue-collar type."

I think it's reasonable to say that this introduction suggests a middle class snobbishness towards the lower class. The worry is that by not teaching the kids correctly, the kids will end up in the lower class.

On the other side, it's also teaching people that they shouldn't want to be in the upper class, because then they would lose this important sense of money.

The hairiness of a hobbit's foot, his lack of shoes, the bright colors he wears and the pipe-weed he smokes are not very relevant to the War of the Ring. But mentioning it in the very beginning certainly helps to set the scene.

Don't be obtuse. What color was her hair? How tall was she? What was she wearing? None of that detail is present. This isn't scene-setting. It's a subtextual comment, and it's a clumsy and ignorant one. That's what bothered me about it: it's just bad writing. We get it, we get it: the author thinks lower-middle class families raise fat kids on junk food. Aha! There's one now!

He also mentioned that her father was "tall and muscular". What's the secret inner meaning of that?

A few small details are enough to generate immersion. The fact that you believe they were lower middle class in spite of the fact that he didn't mention it suggests you created a mental picture. I did too - in my mind the man was black, white t-shirt, a bit of grease on it. That's how the mind works, and writers exploit it.

"He was tall and muscular, a blue-collar type"

A blue collar worker is lower class by definition. As phrased above, the "tall and muscular" bit is part of the writer's observation/stereotype that the man is a blue collar worker. "He was big and strong and (therefore) looked like someone who works in manual labour".

Blue collar is manual work which is not the same thing as lower or lower middle class.

I don't think you seriously believe that this is an example of a writer simply trying to make the mental picture he was painting more vivid.

Look, I read it totally differently than you did. I don't think the secret inner meaning is remotely as clear as you are making it out to be.

OK, I'll let it go.