Science

I Drink It Just for the Death of It

Recently, I ordered a soda along with a club sandwich at my local diner, and the waitress, a snappy little firecracker we’ll call “Beth”, because . . . well, because her name is Beth, asked me wryly, “Leaded or unleaded?”

“Leaded,” I responded firmly, indicating I wanted regular soda as opposed to diet soda.

And it’s a good thing I drink regular soda, because diet sodas will KILL YOU!

Okay, so maybe they won’t necessarily kill you; at least not instantly, unless you have a mouthful of Pop Rocks in your mouth when you take a drink, and then . . . . I don’t know . . . simultaneously shoot yourself in the head or jump into a wood chipper or something.

But according to The New York Times and a study by scientists at the University of Minnesota, diet soft drinks just might do some severe damage in the long run. It seems there is a correlation between drinking diet soda and metabolic syndrome.

And before you get excited, metabolic syndrome is not a good thing.

For the uninitiated, which I admit to being until I read the article and then Googled like I was looking for a freaky farm animals porn site, metabolic syndrome is defined as the collection of risk factors for cardiovascular disease and diabetes. It includes all the little things in life that Americans enjoy so much — and for the most part, take for granted — like obesity, high cholesterol rates, and high blood glucose.

Mmmmm . . . . blood glucose. I sure could go for a nice blood glucose float right about now.

But anyway, the data from the study show:

. . . [T]he risk of developing metabolic syndrome was 34 percent higher among those who drank one can of diet soda a day compared with those who drank none.

Now, as she scribbled down my order, Beth revealed to me that she prefers unleaded sodas to regular, even though I didn’t ask her and really didn’t care. I mean, I like Beth, because in the diner, she is the bringer of delicious food, and that goes a long way with a connoisseur of charred animal flesh such as myself. But her particular soda habits are about as important to me as Hillary Clinton’s preferred color of pantsuit. It doesn’t hurt me in any specific way, but then it doesn’t help me either.

However, I didn’t think Beth’s choice was unusual. In fact, if guessing, I would say that most of the women I know opt in favor of diet sodas over the sweet sweet nectar of a regular soda.

Also, I recall some pretty hefty girls that lived in my dorm — way back in the olden days when I was in college — who loved diet sodas. They would each eat a large supreme pizza and some hot wings, but they would wash it down with a diet soda, thereby, I suppose, breaking even. Whatever the case, the girls loved them some diet soda.

But that memory of my college days got me to thinking more critically about this study.

Now, I’m not one to question peer-reviewed papers very often, but I figured sodas are a staple in Western culture, and everyone can relate to this, so what the hell. It might be fun to discuss.

So, I have two questions for the Skepchicks (and Skepdudes, too):

1) Do you prefer diet soda or regular soda?

and for those of a more inquiring, scientificy, skeptical bent,

2) Do you think it’s possible the people from the study who drank diet sodas already exhibited other elements of metabolic syndrome, like obesity, that could lead them to drink diet sodas?

Sam Ogden

Sam Ogden is a writer, beach bum, and songwriter living in Houston, Texas, but he may be found scratching himself at many points across the globe. Follow him on Twitter @SamOgden

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48 Comments

  1. I drink diet, because I am diabetic and thus not allowed regular drinks. (Diet is recommended.) The sugar content is an important factor. Also not allowed juice and orange juice (which I love) is right out…

    The risk comparison is between those who drank diet and those who didn't, which doesn't necessarily compare those who drink diet with those who drink regular (one would read from the note that the default was no drinking).

    The actual study says "The diet soda association was not hypothesized and deserves further study." which (while the sort of thing one might say to get more money ;) ) would seem prudent to check first.

  2. 1) On the rare occasions that I drink soda, regular. I'm more of a water, coffee and tea guy, myself.

    2) Ah, the old "correlation equals causation" fallacy rearing its ugly head yet again… You had me going for a while there.

  3. Another survey?

    …fine…

    1) Diet. I switched after I noted that running for an hour burned as many calories as I drank in 10 minutes in my soda. As a side benefit, I was able to tighten my belt by two notches within three weeks of kickin' the sugar to the curb.

    2) I would like to see another study which controls for self-selecting factors like high caffeine use, obesity, and age.

  4. I drink Diet Coke like it's going out of style. Which apparently it's about to. HA. Anyway, my predilection for the stuff combined with my natural skepchicky nature leads me to proclaim CORRELATION DOES NOT EQUAL CAUSATION! Now excuse me, I'm off to the vending machine for another hit so I make it to 5:30.

  5. Hehe . . . Sorry, didn't really mean to make a survey. You all are not required to state your preference if you don't want to.

    I read the article and started wondering about some of the data, so I thought I'd initiate a discussion here.

  6. Answer to 1

    I rarely drink soda anymore. When I do it is usually diet but not always.

    Answer to 2

    The article states (After adjustment for demographic factors, smoking, physical activity, and energy intake,)

    It sounds like they took into account things like obesity.

    I think further studies on the effects of diet soda are in order but I doubt anyone should panic.

  7. Er…the quote you cite seems to indicate that the risk is higher for metabolic syndrome when you drink diet soda *compared to drinking none*, not compared to drinking regular.

  8. 1) I don't like the flavor of nutrasweet, and thus avoid diet sodas. For a while I drank Fresca because it was free, flavorful, and wouldn't drive my blood sugars through the roof. I stopped because of the intense headaches. Now my main drink of choice is unsweetened seltzer. When I drink sweetened sodas, HFCS or sucrose is my sweetener of choice.

    2) Since metabolic syndrome tends to be defined by the same sort of stuff which drives people to drink diet soda instead of sugared sodas (weight, diabetes, etc) I would tend to suspect that if there is a causation behind the correlation it's metabolic syndrome is driving diet soda consumption, not the other way around.

  9. 1) Regular. Most of the time. There are a few diet sodas (or pop, as we call it here in the great white plains of MN) that I am ok with. I gave up with the whole thing about a year ago after two years of exercise and diet, during which I gained 15 lbs. Since then, I've tightened by belt two notches. Go figure.

    2) Definitely, it could.

  10. 1) If I drink soda, which is about once a month at the most, it is regular. I don't think either kind is a good thing.

    2) I am a food Nazi, so I think soda is bad, whatever stripe. I don't even give my kid fruit juice because according to all the dentists I know, it is just as bad for causing tooth decay in kids as soda and they get more nutritional benefit from, you know, eating fruit.

    I don't care what the studies say. Moderation in all things, and I don't think a can of soda a day could be considered moderation. But I'm a food Nazi. Ask my husband.

  11. Oops, forgot to say:

    I am always the first one to shout CORRELATION is NOT CAUSATION! But, Americans are fat and unhealthy, and there has to be some cause there at the bottom of it, somewhere. So yeah, I think it's possible that diet soda-drinkers are a self-selecting group based on other problems, but I think it's possible that there's a causative factor there. It's like the whole high-fructose corn syrup thing. The further you get from compounds that occur in nature, the more likely it seems that our bodies might not know how to deal with them properly when we shove them down our food holes in vast quantities.

  12. No. For a food Nazi, you’re actually kind of tight-lipped. LOL, well, I don't know if you've been reading my comments on Vegetarianism on the Harm thread… I will say that I don't enjoy telling others what to eat (just my husband), I just enjoy food and telling everyone else about what I like to eat.

  13. Let's see, I switched over to diet a couple years ago for the twin reasons that my dentist says it's easier on the teeth (not perfect, mind you), and because it has fewer calories (not zero, but pretty damn close).

    Now, the problem of course with a study like this is that it isn't an actual experiment: It just observes behaviors already in effect. There's no way they can control for every possible confounder, so results like these aren't particularly meaningful. There are just too many other ways a correlation could arise for me to think there might be a causal relationship.

    Beyond that, it seems to me that if you were instead to compare diet soda drinkers to regular soda drinkers (and adjust for appropriate factors), you'd find that the calories from the sugar in regular soda would cause an even greater increase in all these sorts of metabolic syndrome. Even if diet drinks are worse than no soda, they're still an improvement for most people who'd drink soda anyways.

  14. I usually don't drink any soda, but when I do, I drink regular soda. In my quest to debunk the Atkins Diet, I read a lot of biochemistry studies on the effect of different artificial sweetners on your metabolism and blood sugar. Let me tell you, it's not much different from real sugar, which probably is what leads to the metabolic problems. But, high-fructose corn syrup is pretty bad too. Why do we even need to drink soda? I just drink water. Has anyone had regular coke in foreign countries, where they use pure sugar to sweeten it, yumm.

  15. Funny you should bring this up. I got a very nice card a few weeks ago from the Diet Coke people. It said, "Thanks." Probably has something to do with my 1×10^40 Coke rewards points. It's ok, though, 'cause a swish told me in a dream that Diet Coke is totally not responsible for any health problems. Also, Coca Cola says it's safe, so…

  16. I'm in the group of people who seem to get severe headaches from Nutrasweet so I never drink diet soda. I've cut wayyyy back on regular soda both to lose weight and because of recurring kidney stones (not that soda causes kidney stones, but I'm supposed to drink a lot of plain water, thus, less soda).

  17. I don't drink anything with aspartame in, because it tastes absolutely disgusting to me. Fortunately for both of us, my wife has exactly the same reaction to it, so we just don't have it around at all.

    As for the second question, it is perfectly possible, but I've no reason at all to think it might possibly be true.

  18. It totally depends on the soda. Diet Coke is fine, but I'd rather drink anti-freeze than Diet Cherry Coke.

    In fact Coke is the only soda I drink diet. And I rarely have soda anyway, I'm a water girl.

  19. Well, I don't eat or drink diet/lite anything.

    Of course, my biggest concern would be to keep my weight up, not down.

    But at the same time, this plays a part too:

    flygrrl wrote:

    It’s like the whole high-fructose corn syrup thing. The further you get from compounds that occur in nature, the more likely it seems that our bodies might not know how to deal with them properly when we shove them down our food holes in vast quantities.

    Why consume artificial shit when the real thing tastes just as good and has been evolutionary proven to be compatible with our digestive system over millions of years.

    As for aspartame, I've used it once, accidentally, in the US about a decade ago. Just one tiny little sachet of it made my iced tea taste waaay too sweet. On the other hand, I could've easily dropped about half a dozen sachets of ordinary sugar in before it would taste anywhere close to the same.

    I wouldn't really know about the correlation between American soda-sweeteners and headaches. Whenever I'm there, I have far too many other contributing factors (not in the least jet-lag, and skeptics-parties) to make any decisive statements about their influence.

    For what it's worth, apart from the first night in Vegas, I can usually go on drinking without hangovers the next day during the rest of TAM. Perhaps I'm just too tired to feel like crap at that point :D

  20. 1) If soda at all and I have the luxury of choice, Coke, regular, light on the ice. Otherwise, it's water (fizzy) or tea (looseleaf), unsweetened.

    2) It seems that a study with 9,500 people in it, tracked for 9 years, would seem to have some statistical power to it. But two points I would make, unfortunately in a long-winded way:

    (a) If I'm reading the abstract correctly – and I may not be – this is a reanalysis of previously collected data, gathered by subjects' self report, so it's possible a variety of interesting errors could creep in, isn't it? People lie, don't recall things accurately, or don't report things fully. (Does shake-n-bake chicken get reported as "chicken" or "fried chicken" or "baked chicken"? Those responses make a difference in this study.) Plus, researchers have to make judgments about coding rules, from how to categorize quirky responses to how to draw a frame around the study – what gets left out may be important. (Did the original study ask about every possible food choice?) Anyway, at best, it seems like this kind of study would only lead to "hmmm….suggestive; study further" results.

    (b) The study authors did not draw any conclusion about the diet soda finding – the correlation/causation fallacy is from the newpaper article. The study abstract (yes, I'm too cheap to buy the article) says: "Conclusions—These prospective findings suggest that consumption of a Western dietary pattern, meat, and fried foods promotes the incidence of MetSyn, whereas dairy consumption provides some protection. The diet soda association was not hypothesized and deserves further study."

    So, let's go scold the NYT! All together now: "Tsk, tsk, tsk!"

    ~fam

  21. I actually prefer Coke Zero to Diet Coke. And, if I recall the labels correctly, the former has more caffeine than the latter, but I'm sure that has nothing to with it…

  22. I tend to drink regular soda. However, I really really like Diet Rite raspberry and grape, so I sometimes drink those two diet sodas, even though (a) I've got the build of the bicyclist I am, and (b) I didn't know those were diet sodas the first time I drank them.

    I think it sounds like the diet soda correlation is not well controlled. As others have pointed out, it is uncertain whether the proper comparison is between diet soda and no soda, or between diet soda and regular soda. I see no indication there is data for non-diet soda in the study, so the correlation may be confounded by pre-existing risk factors, correlated behavioural decisions, or other considerations. This is undoubtedly why the paper says further study is needed.

    That means I'm answering your second question "yes."

  23. (b) The study authors did not draw any conclusion about the diet soda finding – the correlation/causation fallacy is from the newpaper article.

    You're right, but one thing that got my attention was the fact that one of the authors is quoted as follows in the article:

    “Why is it happening? Is it some kind of chemical in the diet soda, or something about the behavior of diet soda drinkers?”

    Seems an ambiguous comment to me, where he/she could emphasize that correlation doesn't necessarily equal causation.

  24. Yep. But I strongly suspect that there was a much longer conversation, and that's the quotation that made it in, while anything more rational about correlation and causation got dumped. I'd bet that the NYT author chose because it's sexier and more provocative than anything any researcher would ever say about the study limitations, the scientific process, and resisting the temptation to over-interpret the data. Cause all that stuff is stodgy and dull, however accurate it may be. Alas.

  25. Ok, so

    1) Diet – I had to give up regular when I found out I was type II diabetic (possibly because of drinking regular sodas…). I also gave up all my favorite foods, too. Ok, maybe not all, but all the deserts. No more "Death By Chocolate" (Geez, they really mean it, don't they) or Double Dutch Chocolate cake, or German Chocolate cake, or chocolate cheese cake, or molten chocolate…. Oh – I'm getting hungry – I'll stop now.

    2) if they're like me, they drink the diet because they already have the metabolic issues.

    jbs

  26. 1) I drink Coke Zero, I find the taste pretty close to normal Coke and am happy not to fill myself with any more sugar than my diet provides.

    2)

    There are lots of reasons to be skeptical about this article/study. (I hope they review it on Science Based Medicine or similar because I'd love to hear Steve Novella's take).

    That correlation does not equal causation is first. Four possibilities for this finding are logically possible.

    A causes B: Artificial Sweetner causes Metabolic Syndrome (by cause I mean increases the risk)

    B causes A: Metabolic Syndrome causes Artifical Sweetner use – this I think is quite possible, those people who are overweight, know their cholesterol is high, know they have diabetes, or have family histories of metabolic syndrom are likely to choose artificial sweetners

    C causes A and B: Perhaps something else causes both metabolic syndrome and choice of artificial sweetners – e.g a love of sweetness leading to the overconsumption of food and sugars leading to metabolic syndrome, but also leading to choice of artificial sweetners which always taste just a little bit too sweet to me.

    4. Or perhaps this relationship is due to random noise. This possibility is especially important because while the p value was low, this was a post hoc analysis not predicted a priori. So this study must be replicated to have validity.

    As someone pointed out these sorts of surveys are prone to biases based on how the answers people gave are turned into the data that is analysed. How to classify shake'n'bake chicken was the example (whatever that is).

    One thing I feel just a tiny bit uneasy about with artificial sweetners is this. Digestion has 4 phases, the first is anticipation where the saliva starts flowing for instance, the second is when the food is in the mouth, you can taste it and it gets secretions going down in the stomach. I just wonder what the effect of tasting something that your body should interpret as being sugary, but not eating any sugar. I'm totally speculating here but if your body responds to this for example by secreting a little bit of extra insulin the rationale being that it is about to get a damn big sugar load, this might lower your blood sugar more than would be ideal. If this happened regularly then it would be a potentially good strategy for the body to start ignoring the insulin a little bit (insulin resistance, or somewhat ignoring the insulin is the problem in Type 2 diabetes – the metabolic syndrome type). Pure speculation but I do feel a little uneasy about tricking the well oiled machine that is the body and its regulatory pathways.

  27. After years of drinking 2 liters or more of regular coke a day, I've switched to diet 7UP. I wanted to lose a few pounds, and I also figured one day it would catch up with me. But I've wondered if I shot myself in the foot by dumping the caffiene with the sugar.

    I'm also one of those weirdos who drinks soda with breakfast. I can't stand coffee or tea.

  28. Coke caffeine, from http://www.energyfiend.com/the-caffeine-database/
    Diet Coke 3.75 mg/oz

    Coke Zero 2.88 mg/oz

    Coke Zero, and the other new Zero brands from Coke, use Acesulfame K as part of their sweetener, for less aftertaste.

    I drink about one diet drink a day, but if I drink more, I have noticed that it seems to stimulate me to crave carbs. It is hard for me to resist. There is a plausible explanation for this, concerning aspartame, serotonin, and tryptophan.
    http://www.dorway.com/walton2.txt

  29. thad – I actually prefer Coke Zero to Diet Coke.

    Same here. I go through WAY too much of the stuff (6-10 cans a day)

    waetherwax – I’m also one of those weirdos who drinks soda with breakfast. I can’t stand coffee or tea.

    Yep. I prefer my caffeine cold and fizzy.

    The biggest red flag on that study for me was that the connection was not hypothesized – that SCREAMS Corr!=Caus to me.

  30. Type 1 diabetes has made me a diet drinker for the last 23 years or so. I do seem to be racking up a lot of the symptoms of Metabolic Syndrome, but that could just as easily be attributed to my tendency toward coach potato-ness.

    In any case, this article seems to be too vague to draw any real conclusions from it. I would like to see some more studies focused on the artificial sweeteners to see if this is a real concern or not. After all, I've known for some time that I should start hitting the gym, but I don't really want to add another necessary lifestyle change in there if I don't have to.

  31. . . . .but that could just as easily be attributed to my tendency toward coach potato-ness.

    My knitting coach in high school was named Coach Potato. Can you believe that?

  32. 1) Do you prefer diet soda or regular soda?

    I'm a Coke fiend, and it's regular all the way, though for health reasons I have finally reduced my consumption down to about a quarter of what it used to be. I cannot stand diet drinks; a few of them will fool my mouth momentarily, but a few seconds of that alum-like aftertaste always alerts me to the fact that someone got my order wrong again. The taste of diet drinks is impossible for me to get used to, so when that's the only soda available, or if I've already had my Coke ration for the day, I'll just drink water or tea.

    2) Do you think it’s possible the people from the study who drank diet sodas already exhibited other elements of metabolic syndrome, like obesity, that could lead them to drink diet sodas?

    I'd say that's a distinct possibility, especially if the study designers didn't think to take such background factors into account when setting up the pool of subjects.

    ~David D.G.

  33. I have seen some discussion somewhere that the term Metabolic Syndrome was created because big Pharm needed a disease before they could sell a drug. It used to be that you were fat and lazy. (Ok, it used to be that I was fat and lazy. I just hate that grammatical "one was fat and lazy".)

    There is a growing concensus that fat is not the problem, but fitness.
    http://www.washingtonpost.com/wp-dyn/articles/A13
    So fat is not correlated to increased mortality, but fitness is correlated to decreased mortality, and fitness is inversely related to fat. It is possible, but not likely, that you are fat and fit. So diets will help you lose weight, but you may not live longer if you don't add exercise.

  34. 1) I prefer not to drink soda and rarely do unless there is rum in it. The rum is sure to make any diet coke worse than a regular coke, so I figure that offsets any potential negative effects.

    2) Yes.

  35. Stacey, nice apples!

    All, I hope someone can point me to a study I read years ago and can no longer find which posited that diet drinks were contributing to obesity because

    your body stopped associating sweetness of taste with high caloric value. This meant that with a diet high in sucralose and saccharine, you can eat a fair amount of sugar without your brain recognizing that your caloric intake is rising.

    I would like to review this study again since I can't recall if it was credible.

  36. msd, I can't help with the study though I can say for sure that a more recent study in the past few months showed that diet soft drinks were very effective in helping people lose weight or maintain healthy weights.

    I can also say that your gravitar is working!

  37. Well apparently I adblocked gravatar some time ago, so I figured out that issue. More importantly:

    xarch said,

    "…my biggest concern would be to keep my weight up, not down."

    We can kill this person now, I mean morally that would be okay, right?

  38. When I drank sodas I always drank the regular stuff. I'm one of those people who gets severe headaches from non-minimal doses of artificial sweeteners (at least the zero/low calorie ones). I do like my Izzes (especially the grapefruit; http://www.izze.com). Dropping the sweet drinks in favor of water/tea was the best thing I did for my figure – I dropped about 20lbs over 6 months (although I was already pretty thin, my face and waist both slimmed down a lot) with the only real change in my lifestyle being the drink change.

    Now soda tastes way too sweet for me. Same with a LOT of things. Ketchup, for example, makes a burger or fries taste like syrup anymore.

  39. msd, I saw an article not to long ago theorizing, based on some studies, that sodas in general were a big part of the obesity problem. The theory goes that our bodies don't recognize nutrients in liquids, so we drink a calorie laden soda, but we're still hungry. I don't think I have it anymore, but I can take a look.

  40. msd wrote:

    We can kill this person now, I mean morally that would be okay, right?

    Well, you would have to catch me first. By the time you do, your BMI may have dropped a point. Sadly, at that moment my BMI would probably also have dropped, below 18 (the lower bound of "healthy").

  41. 1) I drink enough sodas to keep a whale bouncing off of the walls (since I don't drink coffee…), and it's regular all the way for me!

    2) I don't think it really shows anything…

  42. 1) No contest: Fully Leaded. Diet sodas usually taste metallic or bitter or otherwise unpalatable to me. Not that I drink sodas much at all, but when I do it's usually something like a red-cap Blenheim Ginger Ale (although the Coke part of a Rum and Coke would definitely count, too :)

    2) *shrug* I won't repeat the correlation/causation again except by this reference…well covered above.

  43. 1) Coffee. Leaded and straight. Sorry, I don't really drink soda at all. On a very rare occasion, Mountain Dew, straight up and warm.

    2) I think it's possible, but as mentioned above, they seem to have attempted to account for that so in all probability, it's a streetlight.

  44. Correlation doesn't equal causation (repeated again). Exercise people!

    And for the record, Dr. Pepper is my drink of choice. Formerly regular DP, but more recently diet DP.

    Mixed with vodka. Which clearly eliminates any risk of diabetes. Because I don't have it. So there! :)

    But I definitely observe more diet drink consumption versus regular drinks (I refuse to use the term "soda;" it's a heritage thing). I also definitely observe more fatasses than healthy folks.

    So….

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