Wow, no, stunningly wrong.

Being underweight is highly correlated with poor health outcomes in seniors. (https://pubmed.ncbi.nlm.nih.gov/16886095/) Obesity is obviously bad there, but being underweight is just as dangerous.

"In seniors" would be the key word there. For the average American they'd be far, far better off being slightly underweight than being obese.

The parent comment was “I fail to see how in any world underweight is worse unless its a baby.”

Pretty decent chunk of the world is seniors these days.

"is highly correlated". Correlated, not caused by being underweight.

Studies on actual cause has shown the opposite (eating to the point of being underweight raising lifespan).

I was denied life insurance once because I was underweight. Maybe, statistically, it's true.

I have since gained weight and now have life insurance.

Does anyone know if the thresholds for being "overweight" and "underweight" have changed over time? I mean, with so many people getting heavier and heavier has the standard crept up so that "underweight" isn't even skinny anymore?

Typically BMI (mass/height^2), which hasn't changed.

Excluding the fact that average height has increased gradually over time.

I believe they have changed the cut-offs because they noticed that cardiovascular issues started to occur at lower BMI than previously thought.

I didn't know this. Thanks!

It was lowered in July 1998 ("overweight" was reduced to 25 from men: 27 and women: 28)

https://www.nytimes.com/1998/06/04/us/us-to-widen-its-defini...

https://well.blogs.nytimes.com/2014/04/14/a-number-that-may-...

In fact being slightly underweight is one of the only sure ways to increase your life expectancy. Restrictive calories diet.

For many healthy people, losing weight to reach a government ideal of 'healthy' means dropping useful muscle mass. Which is not good.

What. 90% of people do not have any musculature worth talking about. Where are your sources? For 99% of people losing weight will be the problem

Brings to mind the MRI scans of the thighs of an elderly athlete versus an elderly sedentary man https://www.bettermovement.org/blog/2012/use-or-lose-looks-l...

The Army Sergeant Major of the British Army is 'overweight', for example. (He's done interviews about it.) That's obviously nonsense and he doesn't need to lose any weight at all. The idea of 'overweight' is meaningless.

Is he jacked, or fat?

If he's jacked, then yes of course he doesn't need to lose weight. That is a tiny proportion of the population though.

He's jacked, but the original comment was 'losing weight to a target healthy weight is always [ALWAYS] good'. It sounds like you agree that's a false statement?

The original comment was making a generalization that was pretty fair considering that the proportion of the population that has enough muscle mass to cause them to be 'overweight' is pretty small.

Obviously "always" is wrong. Almost nothing is absolute.

> Obviously "always" is wrong.

Bingo.

Since most people are average, there is an average "healthy weight" target. Of course individually, it's really about the ratio of lean mass to fat.

If you define many as like 2% maybe.

GP said 'losing weight to a target healthy weight is always good'. 'Always' is not true.

Well, encumbering "losing weight" with a bad method like losing muscle or breakfast cocaine or cutting fat off your belly with a knife to do it isn't an attack on losing weight, but a misunderstanding of their claim.