22 ms·

Carbonated beverages induce increased food consumption in rats

209 points by vmarsy 9y ago

Etheryte 9y ago
Very, very interesting, mainly because most of the time, the weight gain from carbonated drinks is said to be linked with the amount of sugar. This study, however, suggests that the mere fact that the beverage is carbonated has noticeable correlation with weight gain. Would love to find a link to the paper itself, not just the abstract.
- bognition 9y ago
  https://news.ycombinator.com/item?id=14352942 https://news.ycombinator.com/item?id=14352942
cheath 9y ago
Does this mean that Sparkling Water makes you fat?
- speg 9y ago
  I hope not.. that is my favorite drink. All the bubbles without any of the junk!
  - cheath 9y ago
    ditto. I live off of it.
    - paki123 9y ago
      ditto x2. I think that might be a cause of concern that we are so dependent on it... I hate being paranoid about everything, but if I ever find out my Perrier water has been betraying my trust, I'll have to throw it out like I did soda.
  - swah 9y ago
    Maybe migrate to diet water?
- defined 9y ago
  I used to drink sparkling water exclusively. When I stopped buying bottled water (to reduce unnecessary expenses), I do seem to recall a slightly easier time of avoiding weight gain. But this really means little, objectively speaking; it's just anecdata.
- Etheryte 9y ago
  In addition to testing rats, the study[1] compared five categories of drinks in humans: water, regular carbonated beverage (think soda), diet carbonated beverage (think diet soda), carbonated water and degassed regular carbonated beverage. They measured the release of ghrelin[2], the hormone which essentially tells your body you're hungry. According to their results, both regular carbonated beverages, diet carbonated beverages and carbonated water resulted in noticeably increased amount of gherlin released (see [1] for the specifics). So shortly put, it seems sparkling water makes you hungrier. That doesn't necessarily mean it will make you fat, giving in to the feeling of hunger is always up to you, but feeling more hungry sure as hell will make it likely that you will put on more weight. [1] https://sci-hub.cc/10.1016/j.orcp.2017.02.001 https://sci-hub.cc/10.1016/j.orcp.2017.02.001 [2] https://en.wikipedia.org/wiki/Ghrelin https://en.wikipedia.org/wiki/Ghrelin
  - tomohawk 9y ago
    As far as I can tell, the paper does not include carbonated water as one of the options. It says: "All rats were provided with standard diet Teklad Global 18% protein (2018SC from Harlan Laboratories). Rats of each group were supplemented with different beverages: (i) tap water, (ii) regular degassed CB (DgCB), (iii) regular CB (RCB) and (iv) diet CB (DCB)"
    - deleted 9y ago
      [deleted]
    - jjnoakes 9y ago
      Read page 6: "To extrapolate the study on humans, ghrelin levels were measured in male subjects after drinking any of the aforementioned beverages, in addition to CW (no caloric content, no sugar)."
      - tomohawk 9y ago
        OK, so they didn't do the rat study where they only changed the carbonation (still vs carbonated water), but later it appears they did this for the human subjects and measured the hormone level. It would be interesting to see a study with only that one variable changed to see actual weight gain in animal and human populations. Anecdotal, but I changed from carbonated soft drinks to carbonated water and noted a marked difference.
- marcosdumay 9y ago
  Makes you more hungry. Wether that turns into fat is up to you, but it certainly make it easier to get fat.
mrfusion 9y ago
Does the study suggest any mechanisms of action? I'm wondering if there's an insulin response to a carbonated drink?
- mipmap04 9y ago
  Based on the information in the link: "This is due to elevated levels of the hunger hormone ghrelin and thus greater food intake in rats drinking carbonated drinks compared to control rats." It looks like it's the increase in desire to consume as a result of ingesting carbonated beverages that increases the rate of weight gain.
  - mark-r 9y ago
    Yes, but what's the mechanism that links carbonation with increased ghrelin?
    - cloverich 9y ago
      Comment above suggested it triggered by pressure on the stomach, caused by the CO2 gas as it transitions out of bicarb, which seems reasonable.
      - mark-r 9y ago
        It doesn't seem reasonable to me. Increased pressure would normally come from greater food intake, which should decrease the amount of the hunger hormone. Is this pure speculation, or is there something in the study to back it up?
- mattkrause 9y ago
  As the (real) title says, they think it is linked to ghrelin, a neuropeptide associated with hunger. Drinking something carbonated causes more ghrelin release (or less suppression of ghrelin released, actually) than drinking a still beverage. More circulating ghrelin leads to more hunger, which leads to more eating, which leads to weight gain. The mechanism that allows CO2 to act on ghrelin isn't really clear. They suggest that the bubbles push on the stomach wall, which in turn increases ghrelin release. The whole ghrelin pathway isn't known, but I thought pressure on the stomach walls would suppress, rather than induce ghrelin. There are a few other odd things too. For the rat experiment, they show weight gain curves (weight vs. time) for four groups: rats drinking a) water b) sugar soda c) degassed sugar soda d) diet soda. As you might expect, rats drinking water end up weighing the least, rats drinking (sugar) soda weigh the most. However, the rats drinking the degassed (sugar) soda weigh significantly less than those receiving diet carbonated soda. They take this as support for their theory, but it seems odd that this effect would totally dominate the actual calories in the sugary soda. Similarly, the carbonated (sugar) soda vs. carbonated (diet) soda groups also aren't different.
MichailP 9y ago
Is this true? I once heard that carbonated water is bad for liver, but never found facts to support this (until this paper). Can someone more knowledgeable please comment? People may be destroying their liver and thinking they are doing something good for their health by drinking mineral (carbonated) water...
- mratzloff 9y ago
  This paper still doesn't support that conclusion. It's widely agreed (thus far) that carbonation is harmless. Whether or not this study legitimately challenges that is impossible to say without seeing the actual study.
  - kefka 9y ago
    The claim is: 1. dissolved CO2 is in drink. Is drunk. 2. When liquid containing CO2 is in stomach, H2CO3 drops out of solution to CO2 and H2O. 3. The pressure on the stomach cells with CO2 cause them to release Ghrelin 4. When Ghrelin reaches brain, causes hunger sensation 5. Person eats reacting to hunger sensation
    - cloverich 9y ago
      If that's the case, I feel like saying it induce's hunger / impede's satiation would be a more accurate title.
    - cryptonector 9y ago
      Hunger? That's it? OK. Thanks. For me, CW mostly causes me to... drink more CW. Whereas if ghrelin were to do more than cause hunger, that would be rather interesting then. Oh: "Besides regulating appetite, ghrelin also plays a significant role in regulating the distribution and rate of use of energy.[6]" -wikipedia
    - refurb 9y ago
      Why would pressure on your stomach increase your appetite? Shouldn't it be the opposite?
salzig 9y ago
so, the next iteration of coke light is without sugar/corn-syrup/gas? Interesting.
drcross 9y ago
Its not a great abstract because it doesn't quote increase percentages. Ghrelin is the hormone that make you hungry.
- abandonliberty 9y ago
  Occam's Razor says: p is low but magnitude of effect very small.
mmastrac 9y ago
Hrm, no carbonated water in the study [1]? > The study involved groups of male rats who were all fed a standard diet, but given one of four different drinks: > tap water > regular degassed (flat) soda > regular carbonated soda > diet carbonated soda EDIT: I found an offhand lower-quality reference [2] that suggests they did test carbonated water: > Subsequent tests on human volunteers found that those who drank sparkling water at breakfast had ghrelin levels six times higher than those who had still water. [1] The only details I could find were at http://www.westerntelegraph.co.uk/families/print/Can_fizzy_water_make_you_fat__.nhschoices.1/ http://www.westerntelegraph.co.uk/families/print/Can_fizzy_w... [2] http://www.telegraph.co.uk/news/2017/05/15/fizzy-water-could-cause-obesity-encouraging-eat/ http://www.telegraph.co.uk/news/2017/05/15/fizzy-water-could...
- kelnage 9y ago
  FYI, the paper says: > Rats of each group were supplemented with different beverages: (i) tap water, (ii) regular degassed CB (DgCB), (iii) regular CB (RCB) and (iv) diet CB (DCB) Where CB is carbonated beverages.
  - ohyes 9y ago
    But there doesn't seem to be carbonated water? I think the assumption is that CB and Diet CB, would be something like coke or orange soda or whatever, and that degassed CB would be just coke that was left out so the bubbles dispersed. (Rather than 'soda water' as carbonated water might be called in some places). The obvious experiment would have been to test tap water vs. carbonated water, which makes one wonder if this study is yet another example of p-hacking. (We were testing this other theory and look at what happened in the dataset, let's make a paper on that!)
    - mmastrac 9y ago
      I think they tested on humans separately, at least according to my understanding of the paper (linked elsewhere on ipfs in this thread). Screenshot (CW = carbonated water): https://pbs.twimg.com/media/C_-Rcr_UwAASYae.jpg https://pbs.twimg.com/media/C_-Rcr_UwAASYae.jpg
mratzloff 9y ago
Since I'd have to pay $36 to access the article, I guess I'll just never know if the methods back up the headline. Oh well. A La Croix sounds good about now.
- kefka 9y ago
  https://ipfs.io/ipfs/QmWiFX7bmU365CJPAddsjho4vKVsexi3u8eBE7sRYrALyJ https://ipfs.io/ipfs/QmWiFX7bmU365CJPAddsjho4vKVsexi3u8eBE7s...
  - mtw 9y ago
    How did you get this link? I used the Unpaywall chrome extension and it wasn't able to show me an unpaid version.
    - kefka 9y ago
      Library Genesis: http://gen.lib.rus.ec/ http://gen.lib.rus.ec/ Sci-Hub https://scihub.org/ https://scihub.org/ Also helps if you work for a university that pays these rape-quality fees to access what should be public knowledge.
banashark 9y ago
Whenever these `weight gain linked to soda` studies come up, I'm always confused. I've been told I'm in fantastic shape (>90% in all http://strengthlevel.com/ http://strengthlevel.com/ measurements and under 10% body fat) at the moment, and I used to consume a lot of diet soda every day. At it's worst, I consumed >1 liter a day. For me it was a caffeine source (since I dislike the taste of coffee and never saw the benefit in acquiring the taste) that helped me focus when I needed to get work done (I did a lot of tweaking around with amounts to make sure it was a marked difference and not just a placebo effect for me) and acted as an appetite suppressant so that I could manage my caloric intake without getting distracted by hunger frequently throughout the day. I constantly looked at aspartame/stevia/etc research to see what damage I would be doing to myself. While I couldn't really find much in the way of negative health effects (excluding weight gain, which I never noticed a problem with), I ultimately cut off my consumption because of a semi-irrational fear that either information was hidden by soda-corp et al, or that just because of how these chemicals work that there might be bad effects that just haven't been put under rigorous study yet. As a side note, my metabolism is actually slower than average and I need to eat on average ~10% calories less than any macronutrient calculator says to stay in the shape (low bf + strong) that I enjoy being in.
- SyneRyder 9y ago
  While I'm in nowhere near as good shape as you, I have similar 'anecdata' findings. I spent the last few months this year testing this, partly because I was curious about the Tim Ferriss claim that Diet Coke causes you to gain weight. (I actually wanted to test if I could lose weight just from walking & no diet changes.) Even with my two cans of Coke Zero a day, plus sparkling water with ice and a frappuccino most days, I've been losing weight for 4 months. (20.5% bf down to 16.5%.) I did add exercise, but only walking - I increased my steps up to 16000 steps a day for a while, but I'm back to sub-10000/day now. (Pebble Health has been awesome on my Pebble Time Steel.) Whatever effect carbonated beverages have, at least in my experience, it's easily countered by exercise. Maybe that's not true for everyone, but it seems it's something you can easily test on yourself for a month or two to make your own conclusions.
  - 9y ago
kumarski 9y ago
Humans are not mice.
- kyriakos 9y ago
  without implying I agree with the particular study, mice are being used to test a lot of chemicals that are then used on humans so I'd say there's a high probability that how mice are affected could be similar to humans.
  - mattkrause 9y ago
    And ummm...the paper in question used rats, not mice.
pvnick 9y ago
Fascinating. Would have thought artificial sweetener would be implicated, not the CO2.
maxpert 9y ago
I don't get it... first it was fats, burgers and pizzas. Then a study came out claiming it's sugar. Now carbonated beverages! What do they want me to do? Eat grass and drink water?
- WalterSear 9y ago
  No, just avoid junk food.
- aibottle 9y ago
  Nonono there is so much wrong here. Sample size: 20 people. (Okay what? Are you even trying guys? Releasing something about the the human metabolism with a sample size of 20? Shame on you!) Concluding a weight gain because Ghrelin levels are raised? What? Do you even science? Ghrelin in the first place only tells your brain to look for more food because it signals an empty stomach. Studies on Nutrition don't get me started...
  - anigbrowl 9y ago
    Oh please. It's hard to attract funding for studies, it's perfectly reasonable tos tart with a small sample and tehn ask for funding to do a larger study once you have a working hypothesis.
    - ericdykstra 9y ago
      That doesn't mean it makes sense to make dietary decisions based on these studies.
- geowwy 9y ago
  "What do they want me to do? Eat grass and drink water?" Is drinking water really that absurd?
- brandnewlow 9y ago
  Yes, basically. If you drank water and ate grass with some protein mixed in now and then you'd be much better off. The problem I find with that is it's just painfully boring to do so.
bognition 9y ago
I'm not buying it without a comparison of water to carbonated water. Its long been understood that soda w/o carbonation isn't palatable because its too sweet and animals stop consuming it. However, when carbonation is present it masks the sweetness which result in increased consumption. So I think they're probably measuring a secondary effect here.
- Etheryte 9y ago
  The paper includes carbonated water, see https://news.ycombinator.com/item?id=14352563 https://news.ycombinator.com/item?id=14352563
- theptip 9y ago
  One of the experiments measures serum ghrelin levels in humans after consuming a fixed volume of liquid; you can directly compare degassed carbonated beverage (DCB) and regular carbonated beverages (RCB) in their tables. This controls for the concern you raise above regarding palatability of the beverage, so I don't think that can be a factor there. Critically, there's a statistically significant difference between water and RCB, but not between water and DCB (though the ghrelin level was higher in DCB than water). From my reading of the paper your concern could certainly be relevant in the rat experiment; I couldn't see any attempt to control for or measure the amount of liquid that the rats consumed, so they could have been drinking less decarbonated beverage.
- dahauns 9y ago
  soda w/o carbonation Soda without soda? :) As a non-native speaker, this continually fascinates me...
  - overcast 9y ago
    Soda, is just short for soda pop, which is the sweetened, carbonated water beverage. So soda without the carbonation is just sweetened water. Flat soda is a fairly common term to describe soda that has lots its carbonation.
    - 9y ago
deleted 9y ago
[deleted]
sov 9y ago
It's actually pretty interesting that at ~55 weeks, RCB, DCB and DgCB are in very close proximity to one another, then, suddenly, the non-carbonated beverages (DgCB, water) take a huge drop over the next month, with a bit of a stutter on the DCB and a continuous rise on the CB. I wonder if the significance they see in this study is due to an exogenous reaction with the extra CO2 (eg, an environmental factor).
mtw 9y ago
Q: Are there any effects in drinking natural carbonated water? Such as Evian, Perrier from source. I am skeptical if drinking more Perrier increases your food consumption
- libdong 9y ago
  It makes no difference if the water is naturally carbonated or not. Carbonation is caused by dissolved CO2 (in equilibrium with other carbonates) and there is no way for you body to distinguish between "natural" and "unnatural" CO2.
burntrelish1273 9y ago
Oh crap. I drink a lot of CB flavored (diet) water, take a med which increases hunger and having weight mgmt issues (also taking metformin for dual-purposes of life extension and weight reduction). Probably time to switch to diet flavor drops + plain water, and exercise more.
developer2 9y ago
This comment is a reply to many of the commenters here on HN, rather than a direct response to the article. How do you get to the point of debating the difference between soda vs. diet soda, as if it's a must-have treat and you are "simply" choosing the lesser of two evils? All soda is UNEQUIVOCALLY bad for one's health! You're drinking a cocktail of chemicals that has no nutritional value, and designed to be addictive. Artificial sweeteners are a gimmick to allow us to recuse ourselves from the innate knowledge of what it is healthy. Selecting a supposedly "healthier alternative" is nothing more than a way to grant ourselves asylum from being personally responsible for our choices. We pretend that our "science" is universally proven evidence backed by chemistry and physics, vs. the truth: it's a manmade lie which no enlightened species would tout as being scientifically valid. The same mental masturbatuion occurs with vaping. "Vaping is better than smoking!" As if inhaling any mind-altering drug is necessary to "get by", and so it must surely be "better" to attach oneself to the "least worst option", rather than kicking the habit entirely. If vaping is "better" than smoking, what is better than vaping? Oh right, not inhaling anything other than the air we evolved to breathe. Your body wasn't made to inhale chemicals not produced in nature; it was also not made to drink soda. The fact that you don't die instantly from consuming such products does not mean they are not harmful. The excuses many people make regarding their health is... I'm going to call it what it is: completely and utterly _PATHETIC_. As a species we pretend we are intelligent, but a vast percentage (90-95%?) of the population can't even overcome the most primal appetite for fats, sweets and drugs. Our species will never be capable of rightfully calling itself "enlightened" until we drop all desires for this kind of bullshit. If you're playing mind games with yourself to allow you to "cheat just a little" by consuming unhealthy products, while falsely duping yourself into believing your decisions somehow result in an overall net positive "compared to the (unnecessary) alternatives", you're deluding yourself. Advice to all alien civilizations: avoid us at all costs. Making contact with us cannot possibly be beneficial to you. We'll either bomb you out of fear and ignorance, or bombard you with our capitalist bullshit in order to pull you into our way of living that will ultimately destroy you from the inside out. What makes this truly disgusting is that people who choose to destroy their bodies - by drinking diet soda, vaping, or eating junk food - are in fact aware that they are lying to themselves. You know that you are making the wrong choices, but opt for the fallacy that somehow you are not in control. Nobody really believes the marketing companies are pushing out. People are just looking for someone else to give them permission to be unhealthy, desperately listening for someone to tell them what they want to hear. People know they are too weak to have self-control, and are looking for a voice to be their scapegoat. tldr; Diet soda is not "better" than soda laden with unadulterated sugar. It is simply worse than water, and the fluids you would get from fruits, vegetables, and free-range animals and fish. Allow your brain's thought processes to align with your species' natural evolution. Stop using product manufacturers' claims as a scapegoat. Think for yourself, and don't make excuses. Edit: To those downvoting: do you downvote because my post is too long and you declined to actually read it, or do you refute the facts? I am normally abrasive in general, but what I've said here really is true. Anyone who reads the whole thing, and still downvotes, is someone with their head in the sand. You can be part of the 90-95% of morons I mentioned earlier. Be the reason our species is doomed, for all I care.
GoToRO 9y ago
What one can do is reset your body. Consume your own grown stuff and only drink spring water, from a real spring, and see the effect on yourself for 4-6 months. The problem is that there are a lot of people that grew in urban areas and they don't even know what they are missing. Simply put, most urban areas are designed to be efficient and so not good for you.
- hueving 9y ago
  Naturalistic fallacy. A water filter will do fine and water from a spring can have heavy metals and other chemicals in it that make it significantly worse than city tap water.
  - GoToRO 9y ago
    You can always test it. That was not my point.
nonbel 9y ago
Can anyone even figure out what carbonated beverages were used for this study? Was there caffeine in it, etc? Then they say they started with 16 rats but then elsewhere (when it is mentioned at all) they seem to have 4 groups of triplicates. So it looks like 25% of the data floated away. They also don't mention blinding. Those are the type of basic questions you should ask when you read a paper that will lead you to immediately dismiss something like this in under 20 min.
runeks 9y ago
Studies like these are way too simplistic to conclude anything regarding obesity, in my opinion. An increase in ghrelin levels was measured, but what about all other other hormone levels that were possibly affected as well? The body is a complex system of thousands of equilibria; if an increase in e.g. testosterone levels (which makes the body burn off fat) was also an effect, this may well offset the effect of increased food consumption -- or even overpower it, causing a weight decline as opposed to a gain.
mysterypie 9y ago
Whenever there's a study that says X causes Y, there should be a rule that says you have to say by how much. That's a super-important piece of information. The abstract should state it! If a study says that drinking grapefruit juice shortens your lifespan by a year, then I'll cut out grapefruit juice. If it shortens it by a few hours on average, then even if the study is 100% accurate, it's too small to care about. Especially in news articles, we tolerate this imprecision with health-related findings but not in other areas. You don't see the news reporting that "avalanche kills some skiers". They'll at least tell you "avalanche kills 1 skier and second skier still missing" (unfortunate) or "avalanche kills as many as 350 skiers" (major tragedy).
- nonbel 9y ago
  The problem is that those estimates are conditional on what variables they put into their statistical model, so they are really usually rather meaningless (not that the mere direction is any more reliable, this can switch too). Maybe you can say: "A specific carbonated beverage (batch 1234 from supplier X) provided ad lib via a standard rodent water bottle with sipper tube increased weight gain by 10% over the course of 3 months (as they aged 3-6 months) of male sprague dawley rats bred by Harlan USA in 2015, raised two to a cage, fed Z brand rat chow ad lib (10 % fat content), kept on a 12 hr reversed day/night cycle at 18-23 C with relative humidity maintained between 40-60%. Over the course of the study, the rats were removed from the cage only three times a week: for 10 seconds of weighing in the afternoons MWF."
lerie 9y ago
I do not think this study can prove that carbonated soda causes weight gain, let alone obesity. People (and apparently mice) are not all "built" the same. Obese people need more exercise (or just plain movement of the body) than those who have less weight on their bodies, "it's not rocket science". Sincerely, common sense.
- emodendroket 9y ago
  The very fact that "common sense" can mislead us is half the reason for doing experiments.

209 points by vmarsy 9y ago

Very, very interesting, mainly because most of the time, the weight gain from carbonated drinks is said to be linked with the amount of sugar. This study, however, suggests that the mere fact that the beverage is carbonated has noticeable correlation with weight gain. Would love to find a link to the paper itself, not just the abstract.

bognition 9y ago
https://news.ycombinator.com/item?id=14352942 https://news.ycombinator.com/item?id=14352942

cheath 9y ago

Does this mean that Sparkling Water makes you fat?

speg 9y ago
I hope not.. that is my favorite drink. All the bubbles without any of the junk!
- cheath 9y ago
  ditto. I live off of it.
  - paki123 9y ago
    ditto x2. I think that might be a cause of concern that we are so dependent on it... I hate being paranoid about everything, but if I ever find out my Perrier water has been betraying my trust, I'll have to throw it out like I did soda.
- swah 9y ago
  Maybe migrate to diet water?
defined 9y ago
I used to drink sparkling water exclusively. When I stopped buying bottled water (to reduce unnecessary expenses), I do seem to recall a slightly easier time of avoiding weight gain. But this really means little, objectively speaking; it's just anecdata.
Etheryte 9y ago
In addition to testing rats, the study[1] compared five categories of drinks in humans: water, regular carbonated beverage (think soda), diet carbonated beverage (think diet soda), carbonated water and degassed regular carbonated beverage. They measured the release of ghrelin[2], the hormone which essentially tells your body you're hungry. According to their results, both regular carbonated beverages, diet carbonated beverages and carbonated water resulted in noticeably increased amount of gherlin released (see [1] for the specifics). So shortly put, it seems sparkling water makes you hungrier. That doesn't necessarily mean it will make you fat, giving in to the feeling of hunger is always up to you, but feeling more hungry sure as hell will make it likely that you will put on more weight. [1] https://sci-hub.cc/10.1016/j.orcp.2017.02.001 https://sci-hub.cc/10.1016/j.orcp.2017.02.001 [2] https://en.wikipedia.org/wiki/Ghrelin https://en.wikipedia.org/wiki/Ghrelin
- tomohawk 9y ago
  As far as I can tell, the paper does not include carbonated water as one of the options. It says: "All rats were provided with standard diet Teklad Global 18% protein (2018SC from Harlan Laboratories). Rats of each group were supplemented with different beverages: (i) tap water, (ii) regular degassed CB (DgCB), (iii) regular CB (RCB) and (iv) diet CB (DCB)"
  - deleted 9y ago
    [deleted]
  - jjnoakes 9y ago
    Read page 6: "To extrapolate the study on humans, ghrelin levels were measured in male subjects after drinking any of the aforementioned beverages, in addition to CW (no caloric content, no sugar)."
    - tomohawk 9y ago
      OK, so they didn't do the rat study where they only changed the carbonation (still vs carbonated water), but later it appears they did this for the human subjects and measured the hormone level. It would be interesting to see a study with only that one variable changed to see actual weight gain in animal and human populations. Anecdotal, but I changed from carbonated soft drinks to carbonated water and noted a marked difference.
marcosdumay 9y ago
Makes you more hungry. Wether that turns into fat is up to you, but it certainly make it easier to get fat.

mrfusion 9y ago

Does the study suggest any mechanisms of action? I'm wondering if there's an insulin response to a carbonated drink?

mipmap04 9y ago
Based on the information in the link: "This is due to elevated levels of the hunger hormone ghrelin and thus greater food intake in rats drinking carbonated drinks compared to control rats." It looks like it's the increase in desire to consume as a result of ingesting carbonated beverages that increases the rate of weight gain.
- mark-r 9y ago
  Yes, but what's the mechanism that links carbonation with increased ghrelin?
  - cloverich 9y ago
    Comment above suggested it triggered by pressure on the stomach, caused by the CO2 gas as it transitions out of bicarb, which seems reasonable.
    - mark-r 9y ago
      It doesn't seem reasonable to me. Increased pressure would normally come from greater food intake, which should decrease the amount of the hunger hormone. Is this pure speculation, or is there something in the study to back it up?
mattkrause 9y ago
As the (real) title says, they think it is linked to ghrelin, a neuropeptide associated with hunger. Drinking something carbonated causes more ghrelin release (or less suppression of ghrelin released, actually) than drinking a still beverage. More circulating ghrelin leads to more hunger, which leads to more eating, which leads to weight gain. The mechanism that allows CO2 to act on ghrelin isn't really clear. They suggest that the bubbles push on the stomach wall, which in turn increases ghrelin release. The whole ghrelin pathway isn't known, but I thought pressure on the stomach walls would suppress, rather than induce ghrelin. There are a few other odd things too. For the rat experiment, they show weight gain curves (weight vs. time) for four groups: rats drinking a) water b) sugar soda c) degassed sugar soda d) diet soda. As you might expect, rats drinking water end up weighing the least, rats drinking (sugar) soda weigh the most. However, the rats drinking the degassed (sugar) soda weigh significantly less than those receiving diet carbonated soda. They take this as support for their theory, but it seems odd that this effect would totally dominate the actual calories in the sugary soda. Similarly, the carbonated (sugar) soda vs. carbonated (diet) soda groups also aren't different.

MichailP 9y ago

Is this true? I once heard that carbonated water is bad for liver, but never found facts to support this (until this paper). Can someone more knowledgeable please comment? People may be destroying their liver and thinking they are doing something good for their health by drinking mineral (carbonated) water...

mratzloff 9y ago
This paper still doesn't support that conclusion. It's widely agreed (thus far) that carbonation is harmless. Whether or not this study legitimately challenges that is impossible to say without seeing the actual study.
- kefka 9y ago
  The claim is: 1. dissolved CO2 is in drink. Is drunk. 2. When liquid containing CO2 is in stomach, H2CO3 drops out of solution to CO2 and H2O. 3. The pressure on the stomach cells with CO2 cause them to release Ghrelin 4. When Ghrelin reaches brain, causes hunger sensation 5. Person eats reacting to hunger sensation
  - cloverich 9y ago
    If that's the case, I feel like saying it induce's hunger / impede's satiation would be a more accurate title.
  - cryptonector 9y ago
    Hunger? That's it? OK. Thanks. For me, CW mostly causes me to... drink more CW. Whereas if ghrelin were to do more than cause hunger, that would be rather interesting then. Oh: "Besides regulating appetite, ghrelin also plays a significant role in regulating the distribution and rate of use of energy.[6]" -wikipedia
  - refurb 9y ago
    Why would pressure on your stomach increase your appetite? Shouldn't it be the opposite?

salzig 9y ago

so, the next iteration of coke light is without sugar/corn-syrup/gas? Interesting.

drcross 9y ago

Its not a great abstract because it doesn't quote increase percentages. Ghrelin is the hormone that make you hungry.

abandonliberty 9y ago
Occam's Razor says: p is low but magnitude of effect very small.

mmastrac 9y ago

Hrm, no carbonated water in the study [1]? > The study involved groups of male rats who were all fed a standard diet, but given one of four different drinks: > tap water > regular degassed (flat) soda > regular carbonated soda > diet carbonated soda EDIT: I found an offhand lower-quality reference [2] that suggests they did test carbonated water: > Subsequent tests on human volunteers found that those who drank sparkling water at breakfast had ghrelin levels six times higher than those who had still water. [1] The only details I could find were at http://www.westerntelegraph.co.uk/families/print/Can_fizzy_water_make_you_fat__.nhschoices.1/ http://www.westerntelegraph.co.uk/families/print/Can_fizzy_w... [2] http://www.telegraph.co.uk/news/2017/05/15/fizzy-water-could-cause-obesity-encouraging-eat/ http://www.telegraph.co.uk/news/2017/05/15/fizzy-water-could...

kelnage 9y ago
FYI, the paper says: > Rats of each group were supplemented with different beverages: (i) tap water, (ii) regular degassed CB (DgCB), (iii) regular CB (RCB) and (iv) diet CB (DCB) Where CB is carbonated beverages.
- ohyes 9y ago
  But there doesn't seem to be carbonated water? I think the assumption is that CB and Diet CB, would be something like coke or orange soda or whatever, and that degassed CB would be just coke that was left out so the bubbles dispersed. (Rather than 'soda water' as carbonated water might be called in some places). The obvious experiment would have been to test tap water vs. carbonated water, which makes one wonder if this study is yet another example of p-hacking. (We were testing this other theory and look at what happened in the dataset, let's make a paper on that!)
  - mmastrac 9y ago
    I think they tested on humans separately, at least according to my understanding of the paper (linked elsewhere on ipfs in this thread). Screenshot (CW = carbonated water): https://pbs.twimg.com/media/C_-Rcr_UwAASYae.jpg https://pbs.twimg.com/media/C_-Rcr_UwAASYae.jpg

mratzloff 9y ago

Since I'd have to pay $36 to access the article, I guess I'll just never know if the methods back up the headline. Oh well. A La Croix sounds good about now.

kefka 9y ago
https://ipfs.io/ipfs/QmWiFX7bmU365CJPAddsjho4vKVsexi3u8eBE7sRYrALyJ https://ipfs.io/ipfs/QmWiFX7bmU365CJPAddsjho4vKVsexi3u8eBE7s...
- mtw 9y ago
  How did you get this link? I used the Unpaywall chrome extension and it wasn't able to show me an unpaid version.
  - kefka 9y ago
    Library Genesis: http://gen.lib.rus.ec/ http://gen.lib.rus.ec/ Sci-Hub https://scihub.org/ https://scihub.org/ Also helps if you work for a university that pays these rape-quality fees to access what should be public knowledge.

banashark 9y ago

Whenever these `weight gain linked to soda` studies come up, I'm always confused. I've been told I'm in fantastic shape (>90% in all http://strengthlevel.com/ http://strengthlevel.com/ measurements and under 10% body fat) at the moment, and I used to consume a lot of diet soda every day. At it's worst, I consumed >1 liter a day. For me it was a caffeine source (since I dislike the taste of coffee and never saw the benefit in acquiring the taste) that helped me focus when I needed to get work done (I did a lot of tweaking around with amounts to make sure it was a marked difference and not just a placebo effect for me) and acted as an appetite suppressant so that I could manage my caloric intake without getting distracted by hunger frequently throughout the day. I constantly looked at aspartame/stevia/etc research to see what damage I would be doing to myself. While I couldn't really find much in the way of negative health effects (excluding weight gain, which I never noticed a problem with), I ultimately cut off my consumption because of a semi-irrational fear that either information was hidden by soda-corp et al, or that just because of how these chemicals work that there might be bad effects that just haven't been put under rigorous study yet. As a side note, my metabolism is actually slower than average and I need to eat on average ~10% calories less than any macronutrient calculator says to stay in the shape (low bf + strong) that I enjoy being in.

SyneRyder 9y ago
While I'm in nowhere near as good shape as you, I have similar 'anecdata' findings. I spent the last few months this year testing this, partly because I was curious about the Tim Ferriss claim that Diet Coke causes you to gain weight. (I actually wanted to test if I could lose weight just from walking & no diet changes.) Even with my two cans of Coke Zero a day, plus sparkling water with ice and a frappuccino most days, I've been losing weight for 4 months. (20.5% bf down to 16.5%.) I did add exercise, but only walking - I increased my steps up to 16000 steps a day for a while, but I'm back to sub-10000/day now. (Pebble Health has been awesome on my Pebble Time Steel.) Whatever effect carbonated beverages have, at least in my experience, it's easily countered by exercise. Maybe that's not true for everyone, but it seems it's something you can easily test on yourself for a month or two to make your own conclusions.
- 9y ago

kumarski 9y ago

Humans are not mice.

kyriakos 9y ago
without implying I agree with the particular study, mice are being used to test a lot of chemicals that are then used on humans so I'd say there's a high probability that how mice are affected could be similar to humans.
- mattkrause 9y ago
  And ummm...the paper in question used rats, not mice.

pvnick 9y ago

Fascinating. Would have thought artificial sweetener would be implicated, not the CO2.

maxpert 9y ago

I don't get it... first it was fats, burgers and pizzas. Then a study came out claiming it's sugar. Now carbonated beverages! What do they want me to do? Eat grass and drink water?

WalterSear 9y ago
No, just avoid junk food.
aibottle 9y ago
Nonono there is so much wrong here. Sample size: 20 people. (Okay what? Are you even trying guys? Releasing something about the the human metabolism with a sample size of 20? Shame on you!) Concluding a weight gain because Ghrelin levels are raised? What? Do you even science? Ghrelin in the first place only tells your brain to look for more food because it signals an empty stomach. Studies on Nutrition don't get me started...
- anigbrowl 9y ago
  Oh please. It's hard to attract funding for studies, it's perfectly reasonable tos tart with a small sample and tehn ask for funding to do a larger study once you have a working hypothesis.
  - ericdykstra 9y ago
    That doesn't mean it makes sense to make dietary decisions based on these studies.
geowwy 9y ago
"What do they want me to do? Eat grass and drink water?" Is drinking water really that absurd?
brandnewlow 9y ago
Yes, basically. If you drank water and ate grass with some protein mixed in now and then you'd be much better off. The problem I find with that is it's just painfully boring to do so.

bognition 9y ago

I'm not buying it without a comparison of water to carbonated water. Its long been understood that soda w/o carbonation isn't palatable because its too sweet and animals stop consuming it. However, when carbonation is present it masks the sweetness which result in increased consumption. So I think they're probably measuring a secondary effect here.

Etheryte 9y ago
The paper includes carbonated water, see https://news.ycombinator.com/item?id=14352563 https://news.ycombinator.com/item?id=14352563
theptip 9y ago
One of the experiments measures serum ghrelin levels in humans after consuming a fixed volume of liquid; you can directly compare degassed carbonated beverage (DCB) and regular carbonated beverages (RCB) in their tables. This controls for the concern you raise above regarding palatability of the beverage, so I don't think that can be a factor there. Critically, there's a statistically significant difference between water and RCB, but not between water and DCB (though the ghrelin level was higher in DCB than water). From my reading of the paper your concern could certainly be relevant in the rat experiment; I couldn't see any attempt to control for or measure the amount of liquid that the rats consumed, so they could have been drinking less decarbonated beverage.
dahauns 9y ago
soda w/o carbonation Soda without soda? :) As a non-native speaker, this continually fascinates me...
- overcast 9y ago
  Soda, is just short for soda pop, which is the sweetened, carbonated water beverage. So soda without the carbonation is just sweetened water. Flat soda is a fairly common term to describe soda that has lots its carbonation.
  - 9y ago

deleted 9y ago

[deleted]

sov 9y ago

It's actually pretty interesting that at ~55 weeks, RCB, DCB and DgCB are in very close proximity to one another, then, suddenly, the non-carbonated beverages (DgCB, water) take a huge drop over the next month, with a bit of a stutter on the DCB and a continuous rise on the CB. I wonder if the significance they see in this study is due to an exogenous reaction with the extra CO2 (eg, an environmental factor).

mtw 9y ago

Q: Are there any effects in drinking natural carbonated water? Such as Evian, Perrier from source. I am skeptical if drinking more Perrier increases your food consumption

libdong 9y ago
It makes no difference if the water is naturally carbonated or not. Carbonation is caused by dissolved CO2 (in equilibrium with other carbonates) and there is no way for you body to distinguish between "natural" and "unnatural" CO2.

burntrelish1273 9y ago

Oh crap. I drink a lot of CB flavored (diet) water, take a med which increases hunger and having weight mgmt issues (also taking metformin for dual-purposes of life extension and weight reduction). Probably time to switch to diet flavor drops + plain water, and exercise more.

developer2 9y ago

This comment is a reply to many of the commenters here on HN, rather than a direct response to the article. How do you get to the point of debating the difference between soda vs. diet soda, as if it's a must-have treat and you are "simply" choosing the lesser of two evils? All soda is UNEQUIVOCALLY bad for one's health! You're drinking a cocktail of chemicals that has no nutritional value, and designed to be addictive. Artificial sweeteners are a gimmick to allow us to recuse ourselves from the innate knowledge of what it is healthy. Selecting a supposedly "healthier alternative" is nothing more than a way to grant ourselves asylum from being personally responsible for our choices. We pretend that our "science" is universally proven evidence backed by chemistry and physics, vs. the truth: it's a manmade lie which no enlightened species would tout as being scientifically valid. The same mental masturbatuion occurs with vaping. "Vaping is better than smoking!" As if inhaling any mind-altering drug is necessary to "get by", and so it must surely be "better" to attach oneself to the "least worst option", rather than kicking the habit entirely. If vaping is "better" than smoking, what is better than vaping? Oh right, not inhaling anything other than the air we evolved to breathe. Your body wasn't made to inhale chemicals not produced in nature; it was also not made to drink soda. The fact that you don't die instantly from consuming such products does not mean they are not harmful. The excuses many people make regarding their health is... I'm going to call it what it is: completely and utterly _PATHETIC_. As a species we pretend we are intelligent, but a vast percentage (90-95%?) of the population can't even overcome the most primal appetite for fats, sweets and drugs. Our species will never be capable of rightfully calling itself "enlightened" until we drop all desires for this kind of bullshit. If you're playing mind games with yourself to allow you to "cheat just a little" by consuming unhealthy products, while falsely duping yourself into believing your decisions somehow result in an overall net positive "compared to the (unnecessary) alternatives", you're deluding yourself. Advice to all alien civilizations: avoid us at all costs. Making contact with us cannot possibly be beneficial to you. We'll either bomb you out of fear and ignorance, or bombard you with our capitalist bullshit in order to pull you into our way of living that will ultimately destroy you from the inside out. What makes this truly disgusting is that people who choose to destroy their bodies - by drinking diet soda, vaping, or eating junk food - are in fact aware that they are lying to themselves. You know that you are making the wrong choices, but opt for the fallacy that somehow you are not in control. Nobody really believes the marketing companies are pushing out. People are just looking for someone else to give them permission to be unhealthy, desperately listening for someone to tell them what they want to hear. People know they are too weak to have self-control, and are looking for a voice to be their scapegoat. tldr; Diet soda is not "better" than soda laden with unadulterated sugar. It is simply worse than water, and the fluids you would get from fruits, vegetables, and free-range animals and fish. Allow your brain's thought processes to align with your species' natural evolution. Stop using product manufacturers' claims as a scapegoat. Think for yourself, and don't make excuses. Edit: To those downvoting: do you downvote because my post is too long and you declined to actually read it, or do you refute the facts? I am normally abrasive in general, but what I've said here really is true. Anyone who reads the whole thing, and still downvotes, is someone with their head in the sand. You can be part of the 90-95% of morons I mentioned earlier. Be the reason our species is doomed, for all I care.

GoToRO 9y ago

What one can do is reset your body. Consume your own grown stuff and only drink spring water, from a real spring, and see the effect on yourself for 4-6 months. The problem is that there are a lot of people that grew in urban areas and they don't even know what they are missing. Simply put, most urban areas are designed to be efficient and so not good for you.

hueving 9y ago
Naturalistic fallacy. A water filter will do fine and water from a spring can have heavy metals and other chemicals in it that make it significantly worse than city tap water.
- GoToRO 9y ago
  You can always test it. That was not my point.

nonbel 9y ago

Can anyone even figure out what carbonated beverages were used for this study? Was there caffeine in it, etc? Then they say they started with 16 rats but then elsewhere (when it is mentioned at all) they seem to have 4 groups of triplicates. So it looks like 25% of the data floated away. They also don't mention blinding. Those are the type of basic questions you should ask when you read a paper that will lead you to immediately dismiss something like this in under 20 min.

runeks 9y ago

Studies like these are way too simplistic to conclude anything regarding obesity, in my opinion. An increase in ghrelin levels was measured, but what about all other other hormone levels that were possibly affected as well? The body is a complex system of thousands of equilibria; if an increase in e.g. testosterone levels (which makes the body burn off fat) was also an effect, this may well offset the effect of increased food consumption -- or even overpower it, causing a weight decline as opposed to a gain.

mysterypie 9y ago

Whenever there's a study that says X causes Y, there should be a rule that says you have to say by how much. That's a super-important piece of information. The abstract should state it! If a study says that drinking grapefruit juice shortens your lifespan by a year, then I'll cut out grapefruit juice. If it shortens it by a few hours on average, then even if the study is 100% accurate, it's too small to care about. Especially in news articles, we tolerate this imprecision with health-related findings but not in other areas. You don't see the news reporting that "avalanche kills some skiers". They'll at least tell you "avalanche kills 1 skier and second skier still missing" (unfortunate) or "avalanche kills as many as 350 skiers" (major tragedy).

nonbel 9y ago
The problem is that those estimates are conditional on what variables they put into their statistical model, so they are really usually rather meaningless (not that the mere direction is any more reliable, this can switch too). Maybe you can say: "A specific carbonated beverage (batch 1234 from supplier X) provided ad lib via a standard rodent water bottle with sipper tube increased weight gain by 10% over the course of 3 months (as they aged 3-6 months) of male sprague dawley rats bred by Harlan USA in 2015, raised two to a cage, fed Z brand rat chow ad lib (10 % fat content), kept on a 12 hr reversed day/night cycle at 18-23 C with relative humidity maintained between 40-60%. Over the course of the study, the rats were removed from the cage only three times a week: for 10 seconds of weighing in the afternoons MWF."

lerie 9y ago

I do not think this study can prove that carbonated soda causes weight gain, let alone obesity. People (and apparently mice) are not all "built" the same. Obese people need more exercise (or just plain movement of the body) than those who have less weight on their bodies, "it's not rocket science". Sincerely, common sense.

emodendroket 9y ago
The very fact that "common sense" can mislead us is half the reason for doing experiments.