Read this article on anorexia

[conuly]

New research shows that our assumptions about eating disorders are often wrong — and that many larger-bodied people are starving themselves.

The comments are just full of people who seem to intently believe that if only those poor souls had stumbled across the right weight-maintenance scheme earlier, they would never have developed an eating disorder.

Also, First Law Thermodynamics Bros, who are extremely obnoxious.

I am automatically suspect of their argument that the first law of thermodynamics proves that calories in, calories out will lose the weight because - well, obviously because of the evidence, and to steal their repeated little catchphrase, science both trumps ideology and doesn't care if you believe in it or not - but also because I'm familiar with Creationists who wildly misapply the third law of thermodynamics as some sort of weird "Checkmate, evolution!" line.

Now, the correct response to those creationists is to head them off at the pass with a bored "The earth's not a closed system, this doesn't apply" and then move on.

Looking up the first law, I see this:

The law of conservation of energy states that the total energy of any isolated system (for which energy and matter transfer through the system boundary are not possible) is constant; energy can be transformed from one form to another, but can be neither created nor destroyed.

and double checking isolated system gets me:

1. a physical system so far removed from other systems that it does not interact with them.
2. a thermodynamic system enclosed by rigid immovable walls through which neither mass nor energy can pass.

Am I correct in my understanding that human bodies are not isolated systems and, therefore, we can all save a lot of time by saying "Nope, that doesn't apply here"?

Comments

[flamingsword]

You are correct! And I will be using this argument henceforth.

[siliconshaman]

BTDT... cutting calorie intake doesn't work (for me). You know the thing where people will horde stuff because "they might need it later" despite needing it now? (and thus never actually using it.) Well, I'm pretty sure that's how my body views fat.

Which goes double this time of year because I'm sure it thinks it needs to build up fat reserves for hibernation or something. I'm hungry all the time during autumn and it takes a very conscious and rigorous effort of will not to overeat.

[conuly]

I hope you've only btdt on the weight loss and not the anorexia. If so, I feel ya. If not, *hugs*.

[conuly]

To be fair, it's more of a gotcha than an argument, but honestly, they're so obnoxious they don't deserve better.

[siliconshaman]

Yeah, I've never had to fight that battle thankfully. More leaned the other way for awhile back when I was a teenager, but never seriously. Like I said, I put weight on but losing it is a struggle. Exercise helps but with my crappy joints most forms of it hurt like hell and cause permanent damage if i'm not careful.

I just aim for maintenance and gentle exercise. (well, kinda gentle.. blacksmithing works pretty well without fucking up my shoulders.)

[flamingsword]

Yeah, they really don’t.

[bibliofile]

Not isolated, not enclosed, nope nope nope.

Bodies and biology are squishy and have far more factors going on than a simple chemical reaction done in lab class. People who apply the laws of thermodynamics to anything else (especially human life), well, I see what they mean to do, but too many a) don't understand physics OR biology, and/or b) don't know how to use metaphors properly. (Kids, don't try this at home!)

Excellent article; thank you.

[pauamma]

If they tut-tut you, here are some ways we're not:
- Food and water intake
- Shit (bilirubin, digestive enzyms, gall) and piss outtake
- O2 intake
- CO2 and water vapor outtake (IIRC, exhaled air is at 100% RH)
- Blood outtake (each scratch, cut, wound, blood labwork or blood donation)
- Light intake through the eyes
- UV intake through the skin
- Infections
- Sex
- Pregnancy and periods

[conuly]

Bodies and biology are squishy and have far more factors going on than a simple chemical reaction done in lab class.

Also, biology and chemistry and physics are all much more complicated than your high school textbooks - or 101 college texts! - made them out to be.

I think people either forget that or somehow never realized it in the first place.

[siderea]

Am I correct in my understanding that human bodies are not isolated systems and, therefore, we can all save a lot of time by saying "Nope, that doesn't apply here"?

Technically, you are correct, but it's not a compelling argument because it's pretty easy to model humans as isolated systems. It invites the response, "Oh, really? Where are you suggesting the extra calories escape our bodies?"

There are other, better arguments why the Thermodynamics Abusers* are wrong, but they are more technical and tedious: digestion and metabolism are thermodynamically inefficient processes (like everything, hence the three laws), and it's absolutely the case that how efficient a human (and its microbiome) is at extracting calories from food is a function of many varying biochemical phenomena in the body. Which is to say, it's entirely possible for two people to eat the same diet down to the same amount of calories and one to put on weight and the other not, because the one who doesn't is less thermodynamically efficient and is shitting out some of the calories the other one isn't.

The trivial and obvious example is if one of the two people is lactose intolerant. That person literally cannot extract a single calorie out of lactose, a sugar, and instead it will either be digested by their gut bacteria, which will then be excreted out, or the lactose will simply run through them and come out the other end. Meanwhile, their lactose-digesting control will absorb all the calories from the lactose they ingest, and will do with it whatever their body is using calories for: keeping warm, fighting disease, running marathons, building muscle, or building fat.

It is entirely possible that obesity is substantially the product of some people being (or becoming) more thermodynamically efficient at extracting nutrients from food, a possibility congruent with the fact that fecal transplants have reportedly caused obesity.

* It turns out that as odious as I find fat phobic physicians, the thing that really makes me lose my cool is physicians mistreating my favorite branch of physics.

[conuly]

If it's any consolation, I don't think any of these people have enough education to be physicians OR physicists.

[hashiveinu]

Someone in recovery from "atypical" anorexia here (meaning I never crossed the arbitrary BMI threshold, as most people with restrictive EDs do not. Actually, when I have crossed into "normal" BMI I have looked very ill).

Gwyneth Olwyn has some really good essays about eating disorders, recovery, and weight. I don't agree with everything she says, but she's put some excellent thought into the topic.

Yes, you're correct that human bodies are not by any means a closed system (just like the Earth isn't, as creationist Second Law misusers leave out).

But the argument I think is most compelling is: weight, like just about everything else in the body, is a homeostatic system. Generally, our bodies have a range of weight that they want to maintain - fat people are modeled by fatphobic doctors as eating so much they gain weight, but (as you no doubt have observed) most people stay more or less the same size most of the time, whether they're thin or fat. If you give people more food than their bodies want, they tend to fidget more to compensate. The body is similarly inclined to slow down the metabolism to compensate for too little food. I knew a participant on an ED forum who was measured as burning 900 calories a day. (And her ED treatment team thought that meant that was how much she should be eating. You can't make this stuff up.)

Bodies vary in both their set point and how hard they defend it. I had a cat whose set point was chubby - but she lost weight remarkably rapidly whenever she got sick. She had a higher set point, and also her body didn't defend it very strongly by slowing down her metabolism. She'd go back to her normal size when she recovered.

Cycles of dieting or food insecurity are theorized to adjust the set point upwards. And the "obesity epidemic" (more accurately "population-wide weight gain, putting more people over an arbitrary BMI threshold") has also been measured in wild animals and lab animals, suggesting it's environmental and not behavioral in origin.

One factor that is usually neglected in discussions of weight is that the number on the scale doesn't always represent actual flesh. It's very common to retain a lot of water if you start eating more after having starved. I don't think the linked analysis of this phenomenon is complete, as a lot of people have reported retaining a lot of water, enough to make them very large, for years after they recover. My experience indicates that certain environmental toxins and nutritional deficiencies make hanging on to it much more likely.

Weight is super complicated. Moralizing about it gets in the way of actually understanding it as a phenomenon, which is why most of the published science about it is so bad.

[nancylebov]

I think that what's must wrong with the thermodynamic problem is that it ignores health and quality of life-- the only thing that's important is whether the person loses weight.

I think that anyone who recommends weight loss in general is a stupid murderous piece of shit. This might be a psychological problem at my end-- they might be too stupid to be murderous, but it's a very tempting thought.

[sabotabby]

If it was that simple, almost everyone would be thin. Checkmate, First Law Thermodynamics Bros.

[8hyenas]

Oooo the comments. I, for one, would love to see a decent comparison of (U.S. or wherever I guess) childhood food insecurity and adult obesity.

Then there's this...

https://journals.plos.org/plosmedicine/article?id=10.1371/journal.pmed.1003889

Which is basically that eating certain foods (beans, it's beans.) can expand life expectancy by up to a decade. And it's not even that significant that you adjust for other factors, just add beans. BEANS.


*I am not a serious person, I see there are some thinkers in the comments. I commit to everything I say being 50% correct and having a 100% accurate vibe. Pls do ur own research before over investing in beans. BEANS.

[kengr]

There was also some research from 10 or so years back that suggested that "obesity" had a strong correlation with certain viruses.

But of course, that contradicts the sacred "all fat people eat too much" dogma.

Yes, eating "too much" can make you fat. But the value of "too much" varies a *lot*.

And many things can cause weight gain which your body then tends to maintain.

Untreated sleep apnea led to me gaining 100 lbs. Of which I've lost 30 over a period of *many* years.

[hudebnik]

Well, yes, it's too simplistic to say "the human body is not a closed system; end of discussion." After all, the whole point of "calories in, calories out" is to measure what's crossing the boundary of an obviously-non-closed system. In fact, "calories in, calories out" is probably technically correct as a predictor of weight loss and gain.

But as siderea points out, there are lots of other complexities in the system. Most obviously, you lose "calories" not only through exertion but through excretion (urine, foeces, sweat, breath, etc.), and different people's metabolisms and microflora make this very different from one person to another. And living systems react to external changes by adjusting their metabolism (usually in a negative-feedback loop), so this stuff can also differ for one person from one year to another.

[lilysea]

I read an article about 2 years ago

about a woman who had a giant abdominal cancer tumour (3kg or 4kg when it was finally removed)

and she could eat very little because the tumour got in the way

and every time she went to the Dr

they told her that she was lying about how much she could eat

because "look how fat your stomach is!"

and they refused to do tests because clearly she was just a lying fat woman

[wenchpixie]

100% correct. To the extent that one of my Physics profs used it as a way to shut down a similar obnoxious bit of bullshittery in a pub about 20 years ago.

[wenchpixie]

I mean, beans can be tasty, and they're cheap so it's no great loss even if there's no additional life expectancy affect (which with fibre, etc. there likely is).

[librarygeek]

Thank you, I've been looking for (see profile name!) that pets and wild animals study for years. I read it when it initially came out, internalized it, and never paid any attention to the fat phobia again.

Spouse has done work with the ice core data, climate change, and environmental project management. Our current hypothesis on the population-wide weight gain, with the various species data, is that there's a correlation between some combination of environmental factors and the resetting of the metabolic set points across species. The factor we're watching closely is the ocean currents conveyor belt, because if the earth loses that, there's a lot less inhabitable land for everything. Where's the fresh water and is it too hot for most species? https://oceanservice.noaa.gov/facts/conveyor.html

[the_siobhan]

My way of thinking about it is that "calories in, calories out" is technically correct, it's really irrelevant because we have minimal control over calories out. Exercise uses a tiny fraction of our daily calorie use, and our bodies are very good at learning to reduce our calorie use if we're threatened by famine.

[calimac]

I pretty much agree with this. That the body + its calorie intake is not an ideal closed system is not an important factor here. The problem is the way the body reacts to changes in calorie intake: the "shut down" and "store fat" responses to being starved. It's not a simple in-out system.

[siderea]

One of the things I find most fascinating about people who say "calories in, calories out" is that, in the most literal possible way, they do not mean it. Their hypothesis is "calories in, no calories out". Their model of nutrition and obesity is that body retains calories. They see the body as a roach motel for food: no food leaves the body and all calories are converted to fat. There is no metabolism in their model, the body does not use calories for energy.

[elisi]

Can't read the article, but I've been meaning to share this one which I think might overlap?

Everything You Know About Obesity Is Wrong

[siderea]

Since there's a secondary discussion emerging here about the obesity epidemic, I just wanted to drop in people's ear the fact that we, meaning our planet, are going through something that's been called "the great nutrient collapse". Turns out plants behave differently when grown in different atmospheres, and it turns out a bunch of food crops shift to more saccharides and fewer micronutrients in higher concentrations of CO2. IIRC we've already lost about 8% of micro-nutritional value of a bunch of food crops over the last 50 years.

It's not just us being impacted: there was a study that showed IIRC a drop in the protein content of pollen over ~100 years, probably impacting bees and other pollen-eating species.

(Planning a post about this.)

[the_siobhan]

Well that's not terrifying at all.

[altamira16]

Some large adults I met were anorexics when they were younger. They broke their metabolism with their disordered eating when they were younger.

[hashiveinu]

They might still have a restrictive ED. The point of this article is that you can't tell by looking at them.

[conuly]

Oh, well, they think that health and quality of life = weight, no more, no less.

[melannen]

My reply is generally "The calories in food are measured how much heat an item gives off when it is lit on fire. When your closed body system uses calories by lighting them on fire, get back to me."

[jack]

Am I correct in my understanding that human bodies are not isolated systems and, therefore, we can all save a lot of time by saying "Nope, that doesn't apply here"?

I agree with everything you say, and everything the replies to your post say, and I think that First Law Thermodynamics Bros are wrong about everything, and are also obnoxious and harmful. But I'm not sure that's why they're wrong.

Like, yes, the statement of the laws of thermodynamics by itself isn't enough to model a human body. But it is true that the same principles of the first law of thermodynamics apply in many situations that aren't literally completely isolated, if energy *doesn't* enter the system in other ways. E.g. if someone thinks they've built a perpetual motion machine, the same principle says that either it will run down eventually, or if it keeps going energy is being added in some way they ignored. That argument works even if the "perpetual motion machine" isn't isolated in outer space.

And likewise, the Thermodynanics Bros argument is that "if you exercise the same amount and eat less, you will lose weight", and they *assume* that "and you can do it if you try hard enough" and they *assume* that means that "then you will be healthier with no significant downsides", even though they don't state those parts of their argument. And I think their argument is equally flawed, but I think that the flaw is in the following assumptions, not the thermodynamic statement: if someone tried to follow their plan of cutting food intake no matter what, the flaw in their plan isn't that energy would start coming into their body from somewhere else, the flaw in their plan is that they expect the body to burn away fat first and have nothing else go wrong, but instead some people would experience "body can't keep as active" "overwhelming cravings" "lethargy" "coma" and "death" :( :( :(