Body fat link to bacteria in feces | Hacker News Reader

Body fat link to bacteria in feces

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94 pointsgm-conspiracy79 comments

A recent meta-analysis came out and claimed to show that we don't have evidence right now for a link between obesity and what we've measured so far about the human microbiome [0].

I can imagine a regime where two people with the same diet but with very different bacterial communities would have different health outcomes. It toally makes sense to me that if you have bacteria that are better at breaking down long fats into absorbable molecules, that you'd be getting more effective calories from the same food compared to someone without those bacteria. In fact, this has been shown to work in mice in 2006 [1].

However, in the real world, you aren't living in a sterile cage. You can sample bacteria from the environment and your microbiome is allowed to change in response to your diet. It's possible that in this regime, your diet impacts your microbiome much more than your microbiome impacts the outcome of your diet.

[0](http://mbio.asm.org/content/7/4/e01018-16) - Looking For a Signal in the Noise - Revisiting Obesity and the Microbiome Sze and Schloss, mBio 2016

[1] http://www.nature.com/nature/journal/v444/n7122/abs/nature05... An obesity-associated gut microbiome with increased capacity for energy harvest Turnbaugh et. al., Nature 2006

This is often what happens with meta-analyses: many people have convinced themselves there is a pattern based on limited-but-good data, have asserted so in the literature such that it's almost accepted as fact, and then a meta-analysis actually crunches the numbers and finds little to no statistical support for the claim. A recent well-documented case is that of jellyfish blooms in the oceans:

http://theconversation.com/how-time-poor-scientists-inadvert...

Just to clarify, I'm not saying these people are stupid. But rather that Feynman was very right when he said that the easiest person to fool is yourself.

Animals used for meat production are bred for their feed conversion ratio [1] i.e. how much body mass can they produce for a given amount of food. If this can vary within other mammals, I don't see a reason why it couldn't happen in humans. I'm not sure if it would necessarily be microbiome related.

[1] https://en.wikipedia.org/wiki/Feed_conversion_ratio

While that's true, the hypothesis in the paper is consistent with feeding antibiotics to livestock to improve their feed conversion ratio by decreasing the diversity of bacteria in their microbiomes [0, 1].

[0] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1804117/

[1] https://en.wikipedia.org/wiki/Antibiotic_use_in_livestock

In fact, many livestock are given subtheraputic antibiotic doses[0] to increase their weight gain, but the mechanism isn't known for why it works. In that case it feels like it almost has to be a shift of the bacterial community that causes it.

[0] https://scholar.google.com/scholar?as_ylo=2015&q=subtherapeu...

Surprised this isn't referenced more when people bring up "calories in, calories out"

edit: see my child comment if you somehow think I am arguing against the concept

The point of bringing up calories in, calories out is not to argue that everyone has the same metabolism, it's to point out that weight changes must be related to the difference between calories in and calories out. People may argue it dogmatically, but I think most people saying it will concede that it is strongest when it is in terms of actual calories absorbed vs actual calories burned (Rather than estimates).

Sure, someone that absorbs more calories will have to adjust their consumed calories down more than someone who is less efficient, but if they adjust their calories in to be less than their calories out, they will indeed lose weight over time.

It might seem absurd that people actually say "physics still applies", but they are usually saying it in response to arguments that are physically impossible, not in response to nuanced arguments about weight loss being more difficult in some cases.

Probably because it's still irrelevant to CICO. CICO doesn't tell you how much calories go in or out, rather it tells you to measure them wherever possible and make adjustments based on your weight changes.

It is relevant. You might have thought I meant it debunks it (or supports it), what I meant was it adds color to it. Conversion ratio allows you to quantify the difference from one person to another (the "adjustments based on weight change" you refer to)

I still think calories in health science are the last bastion of phlogiston in any of the sciences. It's a deeply over-simplifying metric that implies a false equivalency. We estimate the calories in food by the amount of heat equivalent they create when burnt. We estimate the calorie usage of a human body by the heat it produces during the effort. None of those estimates do justice to the complex biology and chemistry processes at work: not all calories are equal, they never have been, they never will be. (Humans aren't just heat-producing machines. Digestion is nothing at all like producing raw heat from food.)

ETA: It's the health science equivalent of the physics spherical cow fallacy writ large and taken dogmatically.

Good job, you've expounded on the obvious short-coming of "simplification". Most people have a hard enough time with algebra, how do you expect them to handle the many complexities of human biology and the digestive process. CICO is meant as a starting point in a diet, not a be-all, end-all encompassing idea. The spherical cow exists to simplify ideas so they can be more easily grasped and learned.

The spherical cow is a useful approximation in many contexts. However one wouldn't find many aerospace engineers using it to predict the performance of an aircraft. CICO would be an appropriate approximation for e.g. an ecologist studying food chains. That it's used in the context of human nutrition, however, is nearly as severe an indictment of the field as the fact that all of its studies are sponsored by industry.

Again most people aren't trying to engineer their diets, what they need is simple concepts that provide a good outline of what they need to do to meet their goals. Self-monitoring and self-correction are far more useful than knowing a precise formula of how much meat, dairy, fruits and veggies one should be eating.

Again...

Yes you are certainly persistent but we are talking about the state of nutrition as a science not about rules of thumb that average people can use when thinking about diets. The former and the latter are different things.

Then what point are you actually trying to make here? The original comment I made was that this research is irrelevant in regards to CICO. I stand by that a precise formula for what to eat is largely useless in the everyday sense, unless you're developing something akin to Soylent, which could be considered an engineering endeavor.

The problem with an over-simplification, especially one that leads to a false equivalence (in this case calories != calories because it's an indirect measurement of energy by way of an energy by-product heat), is that it leads to drawing the wrong conclusions. Using CICO as a starting point in a diet is, best case, mostly harmless. On the other hand, it has been shown to be actually harmful to people's self-esteems and generally leads exactly to where we are with a steady stream of CICO "fad of the month diets" that don't produce general, reproducible results and can easily victim blame because "they weren't counting right".

Great, CICO might be a useful superstition for you. I'm not going to stop you from using it just as I'm not going to stop people from consulting their astrology charts. I do take umbrage at anyone that thinks CICO is good science; it really is about as much science as astrology.

> harmful to people's self-esteems

Hoo boy, that's what we need, more people with self-inflated self-esteem issues. I think what you mean is that it's harmful to their immediate gratification response.

> CICO "fad of the month diets"

Could you point one of those out to me, because the only CICO diets I'm aware of are things like Jenny Craig and Weight Watchers (oh and maybe Nutrisystem). Shit like South Beach, Atkins, Low-GI, Keto aren't focused on CICO, but on some other aspect of nutritional content.

From what I've read, and I know I'm veering towards stuff I don't have the place to discuss, both Jenny Craig and Weight Watchers seem to go through fad periods themselves, measurement revamps, have different scoring systems between each other, etc.

There are blogs and tumblrs devoted to the cycles that Jenny Craig and Weight Watchers tend to go through and the abusive victim blaming to people that occurs within their programs, especially to "repeat customers". You might not care anything about that sort of abuse (and in fact from many of your responses seem more than happy to fat shame), but it is a real problem that is hurting real people, compassion would go a long way...

For as long as those two have been around, I would expect that they have had to adjust their system based on the changes in nutritional science and to better balance their scoring systems (much like video games often do).

Abusive victim blaming? Really? You mean people don't like being told they're fat. That the only reason they aren't losing weight is because they aren't staying true to their diet. Don't get me wrong, some people are downright abusive, but that falls on the individual not the diet system. On the other hand if you're a repeat customer to something like this, it really shows you aren't learning how to control your diet on your own (which should be the ultimate goal of these programs, I don't know).

I don't put any stock in blogs that dedicate themselves to finding these stories to share (I consider them something akin to conspiracy websites, very different from, say, Yelp). A program so focused on customer abuse should have closed up shop long ago from a lack of customers.

For as long as those two have been around I'd expect they'd have solved weight loss entirely if it was truly as simple as CICO. I'd assume they would have worked themselves out of a business model. They are both for-profit companies and their revenues rely as much on that fact that they don't actually solve the problem as they do on revamping the system every few years to score new customers or returning old customers.

Superstition? Astrology?

I think you never took a physics class? Please check the law of conservation of energy[1]. A human being is an isolated system, to lose body mass, you need Energy Used > Energy ingested.

We may not measure caloric values of food properly, and depending on our genetics and age our caloric expenditures/activity will vary. However imprecise, comparing caloric values of chips (150kcal/oz) and leeks (16 kcals/oz) should still tell you something.

[1] https://en.wikipedia.org/wiki/Conservation_of_energy

First of all, a human body is not an isolated system from a law of conservation of energy standpoint. A human body is a complex ecology of micro-organisms and chemical processes with different energy needs, storage solutions, masses. A human body is continually interacting with its environments including factors that we are just now starting to truly analyze such as the microbiome, which is the crux of the article referenced here.

But that is beside the point, calories != energy (which is properly Joules now in SI system) on either side of the CICO scale, especially the "energy used" side. It's not just a matter of precision, calories are an approximation to energy at best.

But if you want to argue that calories on the input side are still useful, I get that calories can sometimes be a useful first pass approximation, especially to numbers-minded software folks that like easy metrics, and there are plenty of examples where comparing two calorie numbers gives you a reasonable approximation of the comparative "weight" of foods. But there are also plenty of counter-examples: most Diet Sodas have less calories than their "non-diet" counterparts but the science doesn't seem to bear out that they are "healthier"; olestra chips had lower calories than other chips but were determined to be rather unhealthy to the digestive system and people gained weight eating them... Calories don't tell you anything about what is in the food or how the body will react to it.

I get that as software-minded people we like nice easy metrics, but calories are not a good metric.

Now that was entirely pedantry.

The microbiome isn't excluded from the law of conservation of energy either. Different microbiomes may process food differently, but it cannot extract more energy than is available.

A calorie is a unit of measure of energy, specifically the energy required to increase the temperature of 1g of water 1C. The fact that it is inconsistent based on temperature and pressure doesn't invalidate its definition. It is approximately 4.184J.

Your example of diet soda is completely off the point as well. A lot of poisons have 0 calories, that doesn't make them good diet food. Olestra is another bad example, because the rats in the experiment didn't gain weight from the olestra but from a feedback effect that resulted in further overeating. But you're right in that calories don't tell you whether something you eat is poisonous.

Calories are a good enough metric, but they require regular reevaluation in order to make decisions.

If we want to deal in over-simplifications, from the toroid simplification of the human body the microbiome is entirely external to it and the energy it extracts is way more important than the energy in "food".

I think at this point we both have very different views of who is being pedantic and I don't think we are going to convince each other of anything.

It's kind of like measuring the performance of vehicles by looking only at the chemical energy of the fuel they use and how far they go on a given amount of fuel. Those seem like reasonable measurements, until you try to put jet fuel in a motorcycle or bunker oil in your car. The design, efficiency, and maintenance status of the engine matters a lot.

Well of course CICO is an oversimplification, it's supposed to be. It's meant to be the basis of the diet. Your analogy is about as useful as saying 2-dimensional kinematics doesn't translate to 3-dimensional kinematics because it doesn't have a component for handling the third dimension.

Except it doesn't translate, when you're trying to handle the third dimension. And CICO isn't an effective basis for your diet when there are biological factors with large impacts that CICO simply doesn't address.

What large factors outweigh calorie content? There are plenty of dietary restrictions for things like Crohn's and diabetes, but they're easily worked around without changing overall calorie consumption. Hypothyroidism and other metabolic diseases can't cause weight gain without an overabundance of calories consumed. The fact that someone's BMR lowers because of them is not a bigger factor than how much calories a person consumes.

This strikes me as a classic place to consider whether this link is a correlation or a causation. It's really easy for me to imagine that diets likely to produce a great deal of body fat also produce a home for particular sorts of gut bacteria.

It's less obvious, but it's also not such a stretch to imagine mechanisms for positive feedback, in which some of these bacteria reinforce chemical signals that lead to consumption of more of the food they thrive on.

There have been studies that show stool transplants can suddenly cause massive weight changes in individuals. As is often the case with treatments to IBS. It matches up a lot with this study.

In addition a similar study has been tried on genetically identical twins. The difference being the bacteria.

How someone cultivates these bacteria, still a mystery. It could be antibiotics as much as potato starches.

I'd take any study based on IBD data with a large pinch of salt before applying to the general population.

Anything that improves the state of the colon for a person with IBD/Crohn's/UC will cause a massive weight change. A few years back I had 30 cm of small intestine removed and promptly gained 20 kg in two months (which was a very good thing for me then). That obviously won't happen to someone normal.

> There have been studies that show stool transplants can suddenly cause massive weight changes in individuals.

Which is weird, because:

> "The researchers found the strongest links with visceral fat, participants with a high diversity of bacteria in their faeces had lower levels of visceral fat."

A stool sample decreasing biodiversity sounds counter-intuitive to me

The "massive weight changes" from stool transplants are most often weight loss, to my knowledge.

If so, this would be consistent with increased biodiversity (from the stool transplant) correlating with reduced visceral fat.

At any rate, the interaction is probably more complex than our current understanding, as this is a very new area of research.

It works both ways, but once people doing FMT realized that transplanting feces from an obese person to a thin person makes the thin person gain weight, they stopped doing that. All of the stool banks now screen for obesity and won't accept donors with high BMI. So now you should only see weight loss after FMT, or no significant change.

That is very interesting.

Can you provide any links for this FMT screening process?

Sure, here's one: http://www.openbiome.org/stool-donation/

$40 per stool. Nice.

The 'bad' bacteria compete for resources with the 'good' bacteria and simply dominate them to starvation to a point of insignificance. All that's needed is a stool sample with a quorum.

The host's flora is wiped out with antibiotics before the transpant occurs.

Also, diversity has "the strongest links with visceral fat", it isn't the only parameter linked with obesity (visceral or not).

If a new bacteria can out compete the others out of existence, then it makes sense.

It's also not anything of a stretch to imagine that since gut bacteria are known to play a role in digestion, variations in them might effect the body's utilization of what is consumed.

Its also that while breaking down foods, some bacteria can provide chemicals as by products that indicate to one that they are full. It's perhaps not as clean cut as simple the efficiency of one's biology.

If you eat only fruit, veggies and lean meat, it makes sense that your gut bacteria would be different from someone who eats high levels of processed carbs and sugars. The things you eat already are known to cause body fat.

Links like this do not seem like a leap forward, to me.

Did they control for the critically important variable: the subject's diet?

That's assuming that slim people are always people who eat perfectly healthy. Yet seems we all know that one skinny person who eats the worst food ever, and never gets fat.

Probably because that one skinny person eats jack-all outside of the times you are observing them.

No, it's that some extreme outliers have insane BMRs. It's still a calories-in-calories-out situation, it's just their base calories out is so high without doing anything special it's like a superpower. I've only met a few, but it's a real thing! Most of us go through something similar (but to a lesser extent) in our teen years. A few seem to keep it forever.

I'm curious whether anyone can provide some scientific evidence supporting the theory that these people actually burn calories faster? Seems like it should show up very clearly on their core body temperature (thermodynamics and all).

An alternative hypothesis would be that these people have a less efficient digestive system, so more of the calories just pass through.

Here ya go:

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4535334/

Oh neat, they use oxygen consumption as a proxy for metabolism rate. That's actually really clever.

Still would be interesting to see whether it's correlated with body temperature, or if people with high metabolism naturally shed heat faster.

Most people were simply far more active in their teen years, whether they realize it or not.

What was the name of the startup that would analyze your biome?

http://ubiome.com/

There may be others...

Anybody with fecal transplant experience care to comment?

I had one after having a c. diff infection. Didn't turn into a fatso. I did lose 25 lbs from the c. diff, though, now mostly gained back. We're very unclear about how the microbiome affects us; to be a FMT donor you must be in perfect health: not fat, no mental illness, etc.

A FMT is not a panacea for everything that ails. It can cure c. diff, but the results of it for anything else are much less clear. We don't really know why it works and the long term effects of such a dramatic treatment are unknown.

I don't know that I'd call FMT a dramatic treatment. It doesn't seem any more dramatic than a course of antibiotics, which we know wipes out most of your microbiome and tends to lead to IBS and weight gain, or taking probiotics which are intended to introduce bacteria strains into your microbiome.

Take a look at this book, he Second Brain : The Scientific Basis of Gut Instinct and a Groundbreaking New Understanding of Nervous Disorders of the Stomach and Intestines:

http://amzn.to/2dmlrM4

It touches on how the enteric nervous system has similar structures to the brain and also produces neurochemicals.

Interesting perspective.

How many people does that really describe?

I couldn't easily find statistics but I do know of four people first hand.

One after a coma, one after a horrendous decision to have a liquid only diet, and two after eating something very dodgy whilst climbing.

Lets be honest, it isn't the procedure I would run to tell people that I have had.

"Something very dodgy while climbing"? A frozen animal carcass?

I was thinking more along the lines of some unidentified fungus, but I'm just as curious as you are.

I presume so,

The two of them are prone to drinking games whilst climbing/caving and so it was assumed to be something from that until much later on where it was then suspected to be something touched and inadvertently consumed on their morning climb.

How did it work for them? Did they share results? I've seen that fecal matter transplants (FMTs) have been quite successful in curing C. Diff. infections that are unresolved by conventional treatments.

A friend of mine has his microbiome wiped out by heavy antibiotics administration while fighting colon cancer. After his cancer went into remission, he suffered greatly from IBS. It got bad enough that his doctors thought his cancer had returned and started him on chemo again, despite negative results when testing for cancer. That just made things worse. Eventually he decided the antibiotics caused the problem and that FMT was a possible solution.

It took him a long time to find a doctor who would treat him with FMT; no one in the US or Canada would do it and he wound up having to go to London for a month. The change was immediate. His IBS disappeared completely, he's able to eat foods again that he couldn't touch for several years, he's reversed his drastic weight loss and is healthy again.

I may need to do this. I've become extremely intolerant to ~80% of food types. I'm told it's "IBS" but it's accompanied by neurological symptoms. I've seen dozens of doctors and gotten nowhere (the most "promising" diagnosis was abdominal epilepsy).

I'm not sure why a fecal matter transplant would help if you're having neurological issues.

They're a reaction to food. Limiting my diet eliminates them completely. My doctors agree that it's related to food intolerance. What they cannot figure out is a firm diagnosis and treatment.

The problem is that a very diverse set of foods can cause these reactions for me. It isn't as simple as, say, eliminating dairy. My diet is now very limited, to the point of affecting my general state of health. I'm subsisting on plain chicken, rice, spoonfuls of coconut milk, and a "healthy" fat supplement (containing monounsaturated fat), in addition to 2 restaurant dishes which I can tolerate (I've tried dozens).

If I make a dietary mistake, I basically end up with intestinal symptoms accompanied by neurological symptoms (including externally visible twitches among other things) , not to mention typical allergy-like symptoms i.e. throat constriction, sinus inflammation etc, although I'm told it's not a true allergy, but an intolerance. The doctors I've seen have been stumped. But there's no question it all comes down to the gut. I've heard "abdominal epilepsy" being thrown around (after having done numerous tests) but things have not advanced from there. Other ideas were histamine intolerance, celiac sprue, or crohn's disease but the latter two proved back negative after a small intestine biopsy.

Probiotics do improve my symptoms a bit. Somewhat paradoxically (but not really when you think about it), certain antibiotics also clear up my symptoms temporarily. The neurological symptoms are inseparable from the abdominal ones; they always happen at the same time, and it's always primarily an intestinal issue in terms of how it begins (stomach upset after eating something I'm intolerant to).

To top things off, I'm underweight due to what I'm told is malabsorption.

I've tried to make this post concise but there's a lot going on (and yet a lot I did not mention). I hope this explains why I'm considering FMT.

My friend could have written everything you said. He had narrowed down to a very limited diet and lost a lot of weight because almost everything he ate either came back up or rushed right through him. He hadn't mentioned neurological issues, but he did switch to working at home full time to isolate himself, so that might have been a factor as well.

I'd strongly recommend trying FMT. Whatever downsides and risks there are, can't be any worse than what you're going through.

Frankly, I'm not sure I have the guts to do it, no pun intended. It's a combination of a mental block due to the nature of the whole thing, and fear of permanently changing some of my characteristics (such as being slim my entire life).

out of interest, where exactly did your friend get their FMT done ?

I don't know exactly, and wouldn't be at liberty to say if I did. It wasn't easy for him to find a doctor willing to treat him, because of his cancer. He's now the subject of an ongoing experimental study though, and hopes the results will be published soon and based on that he hopes the doors will open to more people getting this treatment.

Well it's only come up because two of them say it's a wonder treatment and the other two couldn't keep a secret to save their lives.

I can imagine if you had one and it didn't go well you wouldn't be particularly inclined to tell relative acquaintances.

I still have not managed to find the original paper.

There are some here, https://kclpure.kcl.ac.uk/portal/michelle.beaumont.html

Isn't it possible that families tend to eat similar foods/diets and this social construct creates the obesity to begin with?

As a mere reader of this article, my only question is:

Couldn't the bacteria be instead the result of a high body fat percentage?

The gut biome is self reinforcing. If you eat nothing but sugar (simplified example) the bacteria that thrive will be the ones that most resourcefully consume sugar. Other strains will wither away entirely or to a very insignificant state. Some, like yeast, actually kills 95% of the colony and the other 5% eat it, so it can take years to bring under control in people with immunocompromise (autoimmune disease, AIDS). If you eat nothing but fibrous vegetables (another simplified example) then your biome will be very different. And part of what makes you hungry is the nutrients the bacteria in your gut desire in order to maintain the colony. So you eat the right foods, then your body desires the right foods. You can re-program your biome to an extent by eating differently. And that goes for eating good or bad food. So I suspect (but cannot prove) that this is where the effect comes from.

An FMT jumpstarts that process, by introducing a bunch of colonists from a healthy microbiome all at once. Then you just need to nurture the new arrivals with proper diet, which you'll start to desire thanks to their influence. That's easier than changing your diet first (fighting what your microbiome wants) and hoping to pick up enough different bacteria for them to establish themselves.

I wonder what the time for adaptation is?

That is, if I want to keep my gut biome un-optimized for absorbing calories from my diet, how often should I shift my diet from carb-heavy to protein-rich to ...

Give me any bacteria and I will keep the body fat low... you know, by just eating as much as my body needs?

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