Derek Thompson writes in the Atlantic about a mysterious new "health wave" sweeping the United States:
In May 2024, the U.S. government reported that drug-overdose deaths fell 3 percent from 2022 to 2023, a rare bright spot in a century of escalating drug deaths. In June, the National Highway Traffic Safety Administration reported that traffic fatalities continued to decline after a huge rise in 2020 and 2021—and that this happened despite a rise in total vehicle miles traveled. In September, the U.S. government announced that the adult-obesity rate had declined in its most recent count, which ended in August 2023. Also in September, FBI analysis confirmed a double-digit decline in the national murder rate.
This is maybe a little overstated? Three of these things aren't health-related, per se, and both murder and traffic fatalities are obviously just reversions to the mean after a brief pandemic spike.
The only true health-related metric here is obesity, and the news here is a little more ambiguous than Thompson lets on:

The CDC's obesity data is a little fuzzy right now, but it shows a couple of things.¹ First, obesity is down, and has been since 2018. But severe obesity continues to rise, reaching a record 9.7% last year. This doesn't suggest some kind of health epidemic is at work.
For what it's worth, it also doesn't suggest that the obesity decline is likely the work of Ozempic and its ilk. The decline began around 2018, before the Ozempic craze was widespread, and it apparently hasn't affected severe obesity, which you'd expect to be the thing it affected the most. So the explanation probably lies elsewhere.
I dunno. Is it possible that we lost weight during the pandemic? I would have thought the opposite, with so many workers hanging around at home where snacks are everywhere. But who knows? Maybe we all just worried the weight off.
¹Older CDC data showed an obesity rate for 2017-18, but that's missing from the newer data, which has only 2017-2020. I'm not sure why. The data is here and here if you're interested.