When we lose weight, where does it go? • Hacker News Board

Re: When we lose weight, where does it go?

#101

Post by mncharity » Sat, Oct 03, 2020, 1:20 AM UTC

mncharity wrote: post #97

kmm wrote: post #84

Earlier quoted context omitted.

The survey in that study always left me with some complicated feelings. How is it possible that 100% of family doctors get this wrong, and what does this mean for their core competencies? Don't get me wrong, I'm humble enough to understand they know infinitely more than I do, and I respect that their education and experience makes them completely capable of doing their job. But then how can they miss such a trivial u…

> completely capable of doing their job [...] But then how can they miss such a trivial understanding [...] It just doesn't match up. People badly underestimate how very rapidly understanding degrades as you move away from someone's focus of expertise. You might laugh if you heard a conversation "You're a Doctor? Yes, of medieval french literature. Good, what do you think of my blood pressure medication?". Or people…

One place this underestimate hurts, is judging the expertise adequate to create excellent insightful and accessible science education content.

Say you want an introduction to atoms for kindergarten. Surely a first-tier professor of physics is sufficient expertise for this, no? And yet, not so much. For example, it's possible to see an atomic nucleus with your naked eye. But only because their are a couple of oddballs, that can be made to fluoresce visibly. The very good rule of thumb is "high energy, can't see". And that's the confident answer you'll get from many a first-tier chemist and physicist. To reliably learn of the exception, you need someone whose focus is nucleus dynamics. A tiny community. But unless you engage them, you won't know you can include a "this is real! see the glowing dot!" photo. I don't know of any non-visitors at MIT with that focus. So my not-quite joke is that MIT has insufficient domain expertise to write a truly excellent kindergarten intro to atoms. One would need to draw on expertise more broadly for that. (A more common failure mode is being able to field cross-domain questions like "does this story convey the right insights? what might a better one look like?")

So what might it take to pull together a massive breath of expertise to create content? The scale is daunting. A cell bio tome textbook publisher commented on their hundred+ authors, and I not-quite joked "great, and how many for the second page?".

Incentives for researchers are a challenge. But a VR intro cell biology project, pulling in researchers with direct expertise for interviews, reported a recurring problem... of getting them to stop and leave. So intrinsic motivations are significant.

Even recognition there's a need, let alone one worth funding, isn't well established.

And the collaborative tech infrastructure to make this possible... that's not a small endeavor.

Re: When we lose weight, where does it go?

#102

Post by rootusrootus » Sat, Oct 03, 2020, 1:56 AM UTC

ilitirit wrote: post #78

This is misleading in some ways. Even people who are not overweight "lose weight" through exhaling and sweat/urination. It's not really an "interesting" concept. I think the more interesting discussion is around how many people still believe that exercise is a better way to lose weight than simply eating less. Basically, the perspective is entirely wrong. It's not about "losing weight", it's about not putting into yo…

> Well, now you know where that water comes from

Glycogen in your muscles, not fat. That's what the early rapid weight loss comes from.

Re: When we lose weight, where does it go?

#103

Post by mncharity » Sat, Oct 03, 2020, 2:04 AM UTC

divbzero wrote: post #89

mncharity wrote: post #82

Earlier quoted context omitted.

One fun variant of this story is: A tree is made of CO2 from air, water and minerals from the ground, and sunlight. If that wood is burned in a campfire, you get back CO2 in air, and water as vapor, and minerals as ash, and (some of) the sunlight as redder light and heat. A related common misconception is to forget that plants, like us and most life, burn carbohydrates to CO2. Rainforest trees for instance, are only…

Yet another angle on the same story: The oxygen that makes this cycle possible wasn’t always available on Earth. It was the cycle itself (specifically photosynthesis in microbes) that created our oxygen rich atmosphere. [1] I’ve heard of Big History [2] as one effort to weave lessons into a coherent tapestry. Agreed that this is a great way to learn. [1]: https://en.wikipedia.org/wiki/Great_Oxidation_Event [2]: https…

> Yet another angle [...] oxygen [...] wasn’t always available

Yes! For example, flammability scales with oxygen concentration, so at peak, wildfires could be continent-scale. And oxygen as toxic bio waste, which our own cells still struggle to handle safely, ties a bunch of stories together.

> Big History as one effort to weave lessons into a coherent tapestry

Just looking at its solar system intro[1], sigh. Creating content that is correct, accessible, and insightful, is hard. Really hard. And since it's not incentivized, it rarely happens. Introductions to the solar system are often so misleading, engendering so many misconceptions you would need to fight with later if you actually cared, that viewing them is arguably net-negative learning.

Coherence regrettably requires correctness. Else instead of a tapestry of understanding, one has a tangled mess of misconceptions. Having tapestry, connections, helps prune misconceptions, by making it easier to see that something isn't fitting. And by making it easier to explore and thereby spot them. But tapestry also seems more vulnerable to misconceptions. Mangle a bit of tangle and you still have tangle, but not so with tapestry. And misconceptions are pervasive in science education. So it seems both broader scope and better quality are needed. A daunting challenge.

[1] https://www.bighistoryproject.com/chapters/2#our-solar-syste...

Re: When we lose weight, where does it go?

#104

Post by SenorTibbs » Sat, Oct 03, 2020, 2:46 AM UTC

kmm wrote: post #84

hprotagonist wrote: post #5

https://www.bmj.com/content/349/bmj.g7257 Meerman, R., & Brown, A. J. (2014). When somebody loses weight, where does the fat go? BMJ, 349(dec16 13), g7257–g7257. https://doi.org/10.1136/bmj.g7257 >Our calculations show that the lungs are the primary excretory organ for fat.

The survey in that study always left me with some complicated feelings. How is it possible that 100% of family doctors get this wrong, and what does this mean for their core competencies? Don't get me wrong, I'm humble enough to understand they know infinitely more than I do, and I respect that their education and experience makes them completely capable of doing their job. But then how can they miss such a trivial u…

It looks like the question surveyed was just "When somebody loses weight, where does it go?" The reason why FM physicians got this wrong is most likely just a framing issue. It's not a wrong answer; fats are broken down by beta-oxidation and the products are used in oxidative phosphorylation to generate ATP - which is then used for energy.

Honestly the question itself seems opaque and intentionally vague to generate surprising results. It's like asking a chemist "What happens to bonds during IR spectroscopy?" and then when they start talking about induced dipoles you say,"WRONG! The bonds stretch!!"

Re: When we lose weight, where does it go?

#105

Post by ineedasername » Sat, Oct 03, 2020, 4:17 AM UTC

I always figured it was heat. Of course it depends on size & build, but it takes around 1,000 calories/day to maintain body heat.

Re: When we lose weight, where does it go?

#106

Post by Ayesh » Sat, Oct 03, 2020, 4:18 AM UTC

LolWolf wrote: post #2

Water and CO2? (And, of course, some other byproducts, but by and large.) I mean, I think this is a well-known answer, no? Sorry I don't mean to sound facetious, I haven't opened the article, so I may be surprised, but I thought this was standard knowledge (at least, it was taught in middle school and high school, even though that's been a while ago for me).

I learned this from a Ted talk, and surprised me quite a lot. The audience seemed surprised too.

Re: When we lose weight, where does it go?

#107

Post by mikepurvis » Sat, Oct 03, 2020, 4:32 AM UTC

thaumasiotes wrote: post #61

mikepurvis wrote: post #47

Earlier quoted context omitted.

Also relevant if you've ever looked into what a modern "condensing" boiler/furnace is: https://www.ernstheating.com/blog/condensing-furnaces/ A consequence of the secondary heat exchanger is that a bunch of the steam from the exhaust condenses back into water, and unfortunately it's water containing a bunch of heavy metals and other nasty stuff, which usually ends up flushed into the municipal sanitary sewer. Probabl…

> unfortunately it's water containing a bunch of heavy metals and other nasty stuff, which usually ends up flushed into the municipal sanitary sewer. Probably still better than it going up the chimney and into the atmosphere, but it would be nice if there was a way to capture and isolate those pollutants in that relatively concentrated state, before they end up mixed in with everyone's bathtub water. You can't be cla…

No, the point I'm making is that most of what sewage treatment plants do is deal with organics— soapy water, human waste, probably a bunch of clothing fibers, whatever.

Without knowing much about waste treatment processes, I could imagine that it would be relatively easier to extract and isolate heavy metals in a state where they're otherwise just in water, vs once they're extremely diffuse and mixed in with all the rest of it.

Re: When we lose weight, where does it go?

#108

Post by mikepurvis » Sat, Oct 03, 2020, 4:39 AM UTC

Scoundreller wrote: post #51

mikepurvis wrote: post #47

Earlier quoted context omitted.

Also relevant if you've ever looked into what a modern "condensing" boiler/furnace is: https://www.ernstheating.com/blog/condensing-furnaces/ A consequence of the secondary heat exchanger is that a bunch of the steam from the exhaust condenses back into water, and unfortunately it's water containing a bunch of heavy metals and other nasty stuff, which usually ends up flushed into the municipal sanitary sewer. Probabl…

My hope is that this is highly dependent on fuel source. Really bad for coal, medium for kerosene and not a huge issue for natural gas.

Me too, but the reason I have it on my mind is because I was reading the technical manual [1] for the fancy new NG boiler I'm having installed next week, and they specifically list the max concentrations of lead, chromium, cadmium, and other scary things in the condensate water after the neutralizing unit, with a recommendation to check with your my regulations to ensure that it's legal to dispose of this water down the drain.

Possibly it's just an abundance-of-caution thing, but I assume the reason for the warning is that in some places it isn't, perhaps because of stricter environmental standards, or maybe a sewage treatment system which isn't set up for this.

1: https://www.viessmann.ca/content/dam/vi-brands/CA/pdfs/wall-...

Re: When we lose weight, where does it go?

#109

Post by vagrantJin » Sat, Oct 03, 2020, 4:41 AM UTC

ncmncm wrote: post #95

thaumasiotes wrote: post #92

Earlier quoted context omitted.

Treatment plants in general obviously do do that.

If they did, there would not be a huge industry in removing heavy metals from industrial wastewater before flushing to municipal sewer systems.

You make it sound like a conspiracy.

Re: When we lose weight, where does it go?

#110

Post by stubish » Sat, Oct 03, 2020, 5:37 AM UTC

The article does not mention gut bacteria. Does anyone know roughly how much of our food and water intake goes into supporting our gut biome and excreted?

Tapeworms were an early weight loss miracle cure (no idea how effective though), and I'm sure someone will be working on a modern version without the side effects.