Back in the 90s we didn't all have phones in our pockets with high quality cameras. If someone got out a camera, it was a special occasion where people probably looked nice to begin with. On top of that, the pictures you see from the 90s are the pictures people have kept for 20 years - again creating a bias for situations where people looked nicer than they were day to day.

If you exclusively look at pictures from the 90s of people doing mundane things like shopping at a grocery store, they don't look any different from people today (except perhaps with worse fashion sense).

I grew up at a beach town. There really is no debate here. If you go back to the 80s it's even more extreme.

I too grew up in a beach town. It's selective memory.

Combined with an increase in obesity over the last several decades, is saying "it's just selective memory" as strong of a rebuttal?

The average american woman weighed 163.8 lbs in 1999, she weighed 171 in 2020. Average BMI increased from 28.2 to 29.1 in the same time period. Women on average added 2 inches to waist size.

Men went from an average weight of 189.4 to 197.9 in the same time period and BMI went from 27.8 to 29.1. Men on average added 1 inch on waist size.

A 5% increase in weight over 20 years might be concerning from a public health perspective, but it's not something you'd see just by looking at people.

From memory, there weren't as many obese people back in the 80's/ early 90's. Being really heavy was a thing that made a person stand out.

I think it's a lot more common now but that might just be selective memory.

The internet exposes us to astronomically more people than we ever could have seen in the 80s and 90s. Really heavy people are still rare today, but if you look at enough pictures of enough people, especially if these sites showing these pictures self-select for oddities, you're going to see quite a few, which makes them seem much more abundant today than they really are, plus much more rare in the past than they really were.

Again, look at pictures of groups in candid settings and you'll notice similar levels of obesity.

But we have statistical surveys which can assert this without having to look at photos.

Even if I agree, you're citing this as a measure of general/overall health, so testosterone levels are not specifically implicated.

High testosterone levels in men are linked to much higher heart problems, a major cause of early death.

If health has declined and testosterone levels have declined then absent any other information I am going to assume that the decline in testosterone is at best uncorrelated with health. Now, maybe there is a reason to assume that lower testosterone levels are actually healthier but I'm going to trust my eyes for the time being.

By almost any measure, global health has improved and global testosterone levels have declined.

Absent any other information, you should therefore assume...

At the same time you are hiding information by taking the global average as the proper baseline for comparison. This is disingenuous here because the original study picked a US cohort. The factors that are responsible for global health indicators improving might be, at least in principle, cancelled out in the US.