You are correct to doubt the meaning of these words as they are being flung around for the sole reason of providing credibility. Your mistake is coming with scientific thoughts into a discussion that is utterly non-scientific and purely based on making money with buzzword-laden books by turning anything related to food into a weird cult-like experience.

But at least your questions are in an area where I can maybe help out. Carbohydrates are just what the name says: carbon molecules with hydrogen and oxygen attached to them. Complexity of carbohydrates is a spectrum, with formaldehyde being at one end and ultra-complex molecules such as huge amino-saccharides or polymers on the other. Saccharides are sugars, who all belong to the carbohydrate family. As far as nutrition is concerned, most sugars are based on the glucose molecule, that's a unit with 6 carbon atoms typically wound into a ring with six or five edges. Chaining those rings together makes polysaccharides.

Overly long saccharide chains only fit into our sweetness taste detectors at one point, that's one ping each from a huge number of saccharide rings. Smaller sugars (like dextrose) cause a lot more signal by fitting better into the detectors, that's why they tend to taste sweeter. Polysaccharide disassembly starts with enzymes in the saliva of the mouth, that's why some things get sweeter when you chew on them for a while. For people who don't gobble down their food to quickly, that means only small sugar molecules even arrive in the small intestine, where they are further split into monosaccharides which can finally be resorbed through the intestinal wall. The small intestine is ill-equipped to handle longer chains, though, that's why they pass into the large intestine. In itself that's not a problem, but if there is a _regular and large_ amount of this stuff in the large intestine, it will attract microbes that live off it.

So if a lot of sugars regularly make it into the large intestine, chances are there will be a population of bacteria (or worse: funghi) taking advantage of that. It's not like the bacteria cause obesity as some articles suggest, their presence is itself a symptom of a nutritional problem (such as too much intake). Of course sometimes these colonies cause other problems like inflammatory reactions that eventually necessitate flushing them out. But saying those bacteria cause obesity is just the new "I'm not fat, I'm big boned", a mechanism designed to deflect the responsibility for obesity away from a person's behavior.

The digestive system is designed to survive and thrive on a variety of food, but there is also a lot that can go wrong. It's not "evil complex polysaccharides" wreaking havoc and producing energy out of thin air to make people fat, it's (as always) people eating too much who are bringing this upon themselves.

One good thing food cults such as the different "nutrition plans" and "strategies" can do, however, is making people reflect on their habits and generally lower their energy consumption. To make it extra clear: I don't think vegetarianism is one of these cults, but it too causes people to eat more carefully.

Thanks for the very informative comment. I also recognize that a lot of people's understanding of food is scarcely more rigorous than cargo cult rituals, but a few points seem a bit unclear to me.

...It's not like the bacteria cause obesity as some articles suggest, their presence is itself a symptom of a nutritional problem (such as too much intake)....

How do you square this with the claim from the original article that giving mice a toxin produced by gut bacteria (Lipopolysaccharide endotoxin) causes obesity and insulin resistance, and that "[m]ono-association of germfree C57BL/6J mice with strain Enterobacter cloacae B29 isolated from the volunteer’s gut induced fully developed obesity and insulin resistance on a high-fat diet but not on normal chow diet, whereas the germfree control mice on a high-fat diet did not exhibit the same disease phenotypes"?

It's not "evil complex polysaccharides" wreaking havoc and producing energy out of thin air to make people fat, it's (as always) people eating too much who are bringing this upon themselves.

Why, then, do some people become obese when they eat as their instincts tell them, and others do not? For example, I eat whenever I'm hungry, stop when I'm full (or even overfilled), snack frequently while working (mostly nuts, dried fruits, and sometimes Fritos), and yet remain thin, while others eat carefully and remain obese. What's the difference?

> How do you square this with the claim from the original article [...]

I think the article makes some dubious claims, mostly centered around a single human volunteer (!), using a mice experiment to back that up - I'll remain skeptical until it can be reproduced by another team. The inclusion of Traditional Chinese Medicine alone as playing a key role to curing the condition is a huge tipoff that something is amiss.

But even taking all those doubts into consideration, let's entertain the hypothesis that this bacterium does produce signals that make a person eat more. It's possible. But you still acquire the bacterium by eating too much in the first place. It simply couldn't colonize you if you didn't.

> Why, then, do some people become obese when they eat as their instincts tell them, and others do not?

My personal opinion is there are two big factors. First, lifestyle. People eat too much because that's simply how they live their lives. It may be because they only have access to high-calorie food, or because everybody around them eats too much, or because they have made a habit of eating too much. The second group (which I'm a part of) is worse: for them, food is an addiction. Many of them may already eat "healthy", high-quality stuff - so moving away from fast food does nothing for them. Eating simply has the same effect on them as drugs do on other people.

You do not acquire bacterium by eating too much. You acquire them by being exposed to them -- kissing the wrong person, sitting beneath a contaminated window air conditioner blowing on you, etc. Yes, they then need to colonize you to become a big problem. You have zero evidence to support your claim that eating too much is a prerequisite for their ability to colonize you.

I already outlined the mechanism in my first post. Kissing and ACs are not the reason you get these organisms inside you. They are already everywhere. Just by moving through life, you're exposed to a huge variety of enterobacteriae. You wouldn't believe how everything is just covered with E. coli, for example. It's not a matter of staying away from dirty surfaces, or of wiping everything down with disinfectant. These organisms are omnipresent, and it's normal for them to live inside your gut as well. In fact, the majority of them are endosymbionts, and are regulated by their environment. This means whatever comes into your colon determines which bacteria get to thrive on it. This is not my claim, it's basic biology.

I invite you to do the following experiment at home. Get yourself a petri dish and fill it with sterile Agar. Then wash your hands. After that, make some fingerprints in the Agar. Incubate for a few days. You'll be surprised.

Oh, I am very well aware that germs, fungus etc are rampant. But you have to be exposed to a specific one to catch that specific one. There has to be a vector, whether it is a dirty surface or another person or something else. Your view amounts to "vague miasma -- no specific source", which is a view that annoys me. It came from somewhere. It didn't just magically pop into existence from the ether because "you ate too much".

I really don't know how to discuss this with you. You blame everything on "behavior" then claim to have a food addiction. Your view strikes me as rather handwavy, while dismissing a possible specific cause for some individuals: exposure to a pathogen. This is not the first time I have heard this, so I doubt that there is only one study.

No, I likely cannot convince you of anything. But you are equally failing to convince me.

First, let's do away with the hostility. I don't know what I have done to provoke it but it's certainly not worth discussing anything in this manner. It's important not to engage in willful misunderstanding, or conflate separate points I made into some kind of chimera to distort what I said.

> You blame everything on "behavior" then claim to have a food addiction.

This is certainly a gross mischaracterization, and I can only assume you're using it to aggravate me somehow? I invite you to read again what I actually wrote regarding this and several other different issues. I'm not sure if you're just trying to troll me or if you actually want to have a discussion, but I'll just assume you're not trying to behave like an asshole on purpose and move on.

You misunderstood my point about how gut bacteria take hold in the first place. Mostly, enterobacter strains are something which lives inside people's guts anyway. There are several pathogenic strains but this is not what the article is talking about. We're talking about an organism that lives off what you feed it. There is nothing hand-wavy about that. It's just a fact. Just as food intake determines individual weight-gain, the availability of nutrients in combination with its environment determines the amount present of a given gut bacterium. It's also a fact that our daily environment is rich in gut (and other) bacteria.

> It didn't just magically pop into existence from the ether because "you ate too much".

I failed to explain this properly then. People have a certain mixture of different gut bacteria inside them, they also tend to acquire them in the "hand-wavy" manner described above. Now, a bacterium needs to eat in order to survive and reproduce. Different bacteria are optimized to eat different things in different environmental conditions. If E.c. colony size is indeed statistically larger in obese people (a point that still needs to be shown conclusively), the reason for that will be that they get a lot of nutrients under favorable conditions. There is nothing magical about it, just basic biology.

> No, I likely cannot convince you of anything. But you are equally failing to convince me.

It depends where you're coming from. I'm not even sure we're speaking the same language, otherwise I can't explain how some of my points could have come across in such a distorted fashion (even taking into account my infamous inability to communicate). In some sentences you portray my views as exactly the opposite of what I actually said. I really mean it when I say I'm sorry we're at this point, but I'm also unsure what I could have done better.

Also, a meta point: have we done this before? I'm not sure.

I don't recall "doing this before" with you in specific. I recall talking to you. I recall it was amicable, which is part of why I replied at all. But this type thing does happen to me a lot on the internet generally, which is incredibly frustrating for me personally. It also happens a lot on HN specifically: I get dismissed by people who are convinced they know science, thus their vague generalizations and personal opinions apparently do not need to be backed up. Granted, it's a huge sore spot for me, but your latest reply doesn't strike me as remedying that at all, though I do appreciate your willingness to discuss it.

There are a lot of people who are either obese and have tried everything and can't lose weight or are thin and have tried everything and can't gain weight. But your opinion is "some people just eat too much", apparently with no real cause. Equally, you are comfortable with "bacteria are everywhere -- if you eat too much you can grow them". You really aren't willing to admit that different people carry different bacteria due to exposure of some sort and this might be a factor in why some people "just eat too much". In your view, the eating too much has to precede the bacterial overgrowth. Seems awfully convenient. But people don't get AIDS or anything else because "well, germs are everywhere". They get AIDS from an infected lover or contaminated needles or due to exposure to some other specific vector. You can "eat too much" all day long and if you weren't exposed to a specific pathogen, you won't grow it.

I have lost enormous amounts of weight in recent years. I never counted calories. I had zero goal of losing weight. My only goal was to kill off the overgrowth of germs which were killing me. Last year, I lost so much weight, so rapidly that total strangers began stopping me in public places and asking me how I did it. I did not feel like getting into my medical situation, so I made vague noises about dietary changes and walking a lot. However, I am a sample of one, so that will also be dismissed by most members of this forum as "not scientific".

I really doubt this discussion will do much for either of us. I regret making my initial post. I really should know better by now, but my recollection was that you are a very reasonable member of the forum. So I chanced it.

Please have a good evening.

"Last year, I lost so much weight, so rapidly that total strangers began stopping me in public places and asking me how I did it."

How did strangers know that you'd lost weight?

I have lived without a car for several years, so I walked everywhere. Sometimes people would stop me in the grocery store or other place and say "I see you walking all the time. God, you've really lost weight!! What are you doing?" I also worked for an extremely large company. There were probably about 2000 people in the building where I worked. So people I did not know at all would stop me in the hallways at work and ask how on earth I was dropping so much weight, so fast.

I am tall with naturally curly hair and apparently striking features. It isn't terribly uncommon for people to notice me whom I never noticed. That sort of experience goes back at least to high school, where people recognize me and I have no clue who they are. (Edit: This is probably compounded by my crappy eyesight. I sometimes don't recognize people whom I do know until I am practically on top of them.)

I didn't intend to dismiss you, that's why this whole thing struck me as odd. I said some things that I didn't recognize anymore when you repeated them, however re-reading my original post confirms they are still there. They just didn't come across somehow, and I'm entirely ready to accept responsibility for that (maybe it's because English is not my first language). It's just a topic where I didn't expect any bitter misunderstandings, that's why I'm so surprised. For what it's worth, I also made it abundantly clear in my posts above where the line between my opinion and scientific fact is - all the more frustrating you chose to attack me as if that line wasn't there. For what it's worth, I do know bioscience, but I also realize that arguments from authority don't mean much, that's why I don't like to preface posts with "I'm a [insert area of expertise here]". I never said anything amounting to "I'm an expert, trust me", instead I believe this is basic stuff that anybody can understand if they make an effort.

Having discussions with smart people who disagree with me is one of the reasons I enjoy HN so much. But it is no fun if key points are misunderstood, ignored, or repeated out of context. So I really wanted to find out why this was happening.

I won't repeat things I said earlier, but as a summary: I really don't think there can be any contention about the growth mechanism of bacteria. As a point of personal opinion, I have voiced doubts about the study and its methodology. I also expressed a personal theory on two major factors that make people fat, one of which I (somewhat regretfully) tied myself to.

> There are a lot of people who are either obese and have tried everything and can't lose weight or are thin and have tried everything and can't gain weight.

Those two are very different. There is absolutely no doubt that obesity comes from excess intake of energy. None. Some diseases cause the body to grow excess tissue or to store water excessively, but that's not obesity. Failing to gain weight, however, can be down to a lot of factors both behavioral and biochemical.

> But your opinion is "some people just eat too much", apparently with no real cause.

I did not say that or anything even resembling that.

> Equally, you are comfortable with "bacteria are everywhere -- if you eat too much you can grow them".

It's a simplified summary, but it's fair.

> In your view, the eating too much has to precede the bacterial overgrowth. Seems awfully convenient.

I don't think that's convenient for anybody. It's just the only way you can multiply microorganisms to any significant numbers.

> But people don't get AIDS or anything else because "well, germs are everywhere".

That one leaves me a little speechless. HIV is a virus, it doesn't have a metabolism of its own. It's a rogue piece of software that hijacks the human runtime, so to speak. That's an exceedingly bad example, but there are bacteria out there that would be much better suited for the point you are trying to make: Take MRSA for example, because it grows and lives off living human tissue. Contrast that to the enterobacteria we were talking about originally, they live off our waste products. So it's clear why, for example, E. cloacae is directly related to the food you eat, but MRSA is not. MRSA attacks the body and provokes an immune response, E.c. does not. That's also the reason why MRSA is something you contract, whereas E.c. is something which in all likelihood you already have. It's worth repeating that enterobacteria actually lend essential assistance to our digestive system.

> My only goal was to kill off the overgrowth of germs which were killing me.

Now I understand so much better where you're coming from. We could have saved a lot of time... Whatever works for you is fine, I didn't want to sabotage that - nor did I have any idea why my dry descriptions provoked such a visceral response, but now I see why.

> I really should know better by now, by my recollection was that you are a very reasonable member of the forum.

Well, I do think this exchange was worth pursuing in retrospect. I do try to be reasonable, though of course I often fail. I'll just have to try harder :)

I think there can be contention about the growth mechanism. Again, my main "proof" is I got better after being sentenced to death. Trying to talk about that gets me dismissed in the ugliest way possible. On HN, I was recently repeatedly accused of being mentally ill and hounded by someone claiming I was being irrational and overly emotional. I remain baffled that no one seemed to recognize his behavior as irrational and overly emotional. My only crime is telling a truth which people find so fantastical that they feel entitled to claim I made it up. I am at wits end as to how to carry on a rational discussion in the face of that. I am trying to figure out what I need to do to present my case more effectively. But I also frequently wish that I could, conveniently, just shut up about it and let other people keep dying, like they seem to prefer. I don't know how to do that. It is an option I often contemplate. But I seem to be equally unable to do that. One of those "sucks to be me" things.

I really don't wish to discuss this further in this thread. Again: Please have a good evening.

Again: none of those things are actually happening in this thread. I'm not disrespecting you, I'm not accusing you of anything, but I also don't think I'm being irrational. I do believe you didn't really read my entire posts though, but that is more a failure on my part than on yours.

Also, it's actually morning here in Europe. In the spirit of a new day: don't ever shut up, but do lighten up.

Cheers guys, loved reading your debate. Thank you both for contributing!

I think one case where someone might object to your comments is the assertion that obesity is strictly a behavioral problem, in the form of overeating. While that may be strictly true by virtue of the conservation of matter and energy, the word "behavioral" can be interpreted as meaning "chosen," as in, "People are obese because they want to be obese." It may be helpful to note that there are many causes for behavior, including conscious effort, habit, addiction, autonomous instinct, reflex, and perhaps even lipopolysaccharide endotoxin.

Absolutely, I didn't mean to imply that behavior is the same as choice. It didn't occur to me that could even be an issue. It's a neutral term.

To people fighting a personal fight in the middle of the battlefield, neutral terms can become not so neutral very quickly :-).

> Why, then, do some people become obese when they eat as their instincts tell them, and others do not? For example, I eat whenever I'm hungry, stop when I'm full (or even overfilled), snack frequently while working (mostly nuts, dried fruits, and sometimes Fritos), and yet remain thin, while others eat carefully and remain obese. What's the difference?

I really really want to see good quality food diaries for people who claim to eat little but not lose weight. I'd also want to see how much exercise they do. (And not even actual exercise, just how much they move around during the day.)

> It's not like the bacteria cause obesity as some articles suggest, their presence is itself a symptom of a nutritional problem (such as too much intake)

this article suggests the bacteria are causing obesity, and explores it by having a flora transplant into a regularly non-obese mouse that causes obesity in that mouse.