a skeptic is an activist who’s been mugged by the HuffPo wellness section


Over at Grist Tom Philpott has written a few posts about the dangers of diet soda, and I’ve been acting cranky about them on Twitter. To be honest, it’s not that the posts are that bad, or even that I disagree with their gist. I tend to think that soda isn’t very good for me in general, and I avoid artificial sweeteners because (in order of decreasing importance to me) I don’t like the taste, have mostly weaned myself off sweeteners, and put at least some stock in the health case against them. So I haven’t really got a dog in this fight, other than general reactionary impulses. I am also not anxious to get into a big huge debate with Tom, because frankly he knows much more about food science than I do. Besides, he seems like a nice guy.

Still, these posts got my goat. I think it’s because they’re emblematic of a number of rhetorical tics that people use when trying to write scary stories about chemicals. And I hate that shit. The audience for that kind of thing is useless at picking or prioritizing their battles; I tend to think it leads to more anxiety, fewer vaccinated kids, and absolutely no effect on policy or health outcomes (other than those related to communicable disease, of course).

Also, I’m confident that Tom’s a smart guy, so the posts struck me as deliberately engineered linkbait, which I also dislike.

Anyway, the Twitter can of worms has been opened, so let me explain here what bugged me about these posts and made me feel that they were representative of bad online coverage of environmental toxins in general.

Cherry-picking research

This one’s easy. Confirmation bias is real (look around and you’ll see it everywhere, the joke goes). I particularly winced when I read the phrase “Italian researchers”. Admittedly, I don’t know the state of Italian biomedical research. But I do follow some alternative energy stuff, and I can tell you with confidence that that country produces more cold fusion “breakthroughs” per capita than anywhere else on earth. Plus, people smarter than me seem to think the Italian academy is a joke. But hey, if the abstract says what we want it to say…

Succumbing to this temptation is understandable, and I’ve certainly been guilty of it myself.  You need to be shut up in a doctoral program for a very long time to begin to possess any kind of immunity.  Frankly, I doubt that any of us are equipped to truly resist it.  But it’s still irritating to be on the other side of it.

Nomenclature as indictment

Particularly infuriating. Lots of chemicals sound scary, and health writers never resist the opportunity to deploy a 5,4-methylpropylbenzepene or whatever into a laboriously recited ingredient list. But it’s meaningless. The nomenclature got a lot scarier when chemists changed how they name compounds. There were good reasons for doing this (reasons that open data evangelists would find particularly appealing!), but the change does seem to have some unfortunately profound side effects on the human mind.

Similarly, pointing to constituent elements or the chemical class to which a compound belongs is rarely illuminating. At one point in the third post Tom discusses how caramel coloring is made by denaturing starches with heat and “ammonia-based” compounds. A shout-out to something you keep under your sink next to the drain cleaner can’t help but cause alarm. But of course fertilizer is also “ammonia-based”; and nobody seems to worry much when it gets turned into protein and eaten.  If you are Derek Lowe or someone like him, you can start to develop rules of thumb about the biological effects of compounds based on their structure.  If you aren’t, you can’t and shouldn’t.

Tom would probably object to this characterization, as his account goes on to discuss a byproduct of the denaturing process that’s carcinogenic. I’d say that that falls under “cherry-picking research”. In truth, lots of cooking processes produce carcinogenic compounds (the process he describes is not dissimilar to how pretzels are made). Remember the scare over acrylamides in french fries and other oil-cooked carbohydrates from a few years back (or the one over the char on your steak)? Suddenly it became apparent that we were all consuming boatloads of cancer-causing chemicals!  But it turned out that the situation’s more complex than that, and a study suggesting that one component of a food has shown carcinogenic effects (often only in an animal model) isn’t nearly enough evidence to justify a freakout over the food in general.

As another example, consider coffee, a beverage that Tom points to approvingly at the end of the second post. The roasting process produces a huge array of chemicals, not nearly all of which have been characterized and studied, and many of which have demonstrated carcinogenic effects (here’s a Wikipedia link, though like me you’ve probably already heard this elsewhere). But that doesn’t matter, because coffee is categorized under our semi-arbitrary “good/natural” heuristic, albeit perhaps with various qualifying words attached to it in our laughable mental medical tag cloud (parkinsons/osteoporosis/miscarriage/anemia/whatever).

Ignoring scale

Less relevant to this series of posts, admittedly, but a habitual mistake of this kind of writing. Humans are awful at understanding differences of even several orders of magnitude, and authors are even worse at bothering to convey them.  For our purposes, this is a problem on two fronts: both chemical concentrations and the scale of measured health effects. All you have to do is say “there’s uranium in your drinking water!” and people will start going nuts. You know what? There almost certainly is uranium in my drinking water, and yours too. There’s nasty stuff everywhere; you can’t avoid it. Things diffuse! Hell, cosmic rays transmute atoms! But until you quantify the scale and demonstrate the effect, these facts are meaningless. Bad things will get into your body, but usually in very small amounts, and your liver and kidneys will probably have no problem doing their usual kickass job of dealing with them (if the bad thing bioaccumulates, you should admittedly be less sanguine about this; but that’s not applicable to the compounds under discussion).

But this is not how the human mind works. You only have to invoke a substance and a sort of animistic power takes over. It’s homeopathy at an angle. It’s why we have airport security theater. Numbers mean so very little to our idiot monkey brains.

Pretending epidemiology hasn’t been invented

Perhaps I will be accused of a kind of libertarian placidity for this one. That would probably be fair. Still, I think that writers often lead with “we are all unwitting participants in a huge and unethical natural experiment!” and then decline to ask whether any data’s come in from this bit of mad science. And the fact is that it has. “It’s a mixed bag” is the answer that then invariably follows, but that’s sort of telling in itself, right? People have been consuming aspartame for a while now — some of them even doing so while participating in vast longitudinal studies — and it’s just not the case that it makes you start sprouting tumors or hemorrhaging spinal fluid or growing hermaphroditic genitalia. I’m all for getting BPA out of the lining of tins of baby food, but it’s pretty hard to make the case that any of the worrying maybes in Tom’s posts are actually manifesting themselves as health crises. Yes, someone needs to be manning the watchtower; yes, industry has incentives for bad behavior. But in this particular case I think the decades’ worth of rhetorical and scientific stalemate over sweeteners is enough to merit some shrugging and eye-rolling.

Diet sodas are not a serious health problem. They’re just not. It may be that avoiding them is a good idea at the margin — and like I said, I do exactly that, because hell, I don’t enjoy ’em anyway. But it’s hard for me to take myself very seriously as I do so. Sure, I don’t like the idea of methanol in my body, but I dislike it in almost exactly the same way that Scientologists don’t like the idea of thetans in theirs. It’s just a neurotic tic; an echo of a sort of Jungian archetype about impurity; really, a hobby at best. I mean, I still drink alcohol, and exercise less than I should, and go out in the sun a lot when I’m on vacation. Despite this disregard for my health I am still probably among the healthiest people in history, thanks to having enough money and living in America in the era that I do.

But look, perhaps you are healthier still. That is definitely possible! If so, by all means, freak out about aspartame if you want. It just strikes me as unlikely to deliver a very good return on the worry you intend to invest in it.

About the author

Tom Lee


  • I enjoy the back and forth of debate, but am a little offended by the breeziness of the response. Not much engagement with the material I presented; lots of dash-off critiques that evaporate on examination. But okay!

    1) “I particularly winced when I read the phrase ‘Italian researchers.'” …”Plus, people smarter than me seem to think the Italian academy is a joke.” And the link is to some other guy’s breezy blog post. But I wasn’t pointing to research from an Italian university. I was referring to research from the Ramazzini Institute, which, according to the NYT, involves “180 scientists and researchers in 30 countries who collaborate on toxin research.” the Times describes like this (this article was linked to prominently in the second post):

    “While Dr. Soffritti’s methods have drawn some criticism, the Ramazzini cancer lab, which is financed by private bank foundations, governments and 17,000 individual members, has earned considerable credibility since it was founded in 1971 for its pioneering research on chemicals. It was the first research body to do studies showing that vinyl chloride and the gasoline additive methyl tertiary-butyl ether, or M.T.B.E., are carcinogenic, research that eventually encouraged the United States to strictly regulate vinyl chloride and that led 21 states to ban M.T.B.E.”

    2) “Nomenclature as indictment,” thunders Lee. But where? Apparently, he’s referring to my discussion of 4-methylimidazole, a compound tin caramel coloring in colas and otjer dark drinks. If I had left it there — ooh, 4-methylimidazole, scary! — I would concede Lee’s point. But I didn’t. I pointed to a formal petition to the FDA by the Center for Science in the Public Interest, and also the document issued by the State of California declaring 4-methylimidazole a cancer-causing substance. According to CSPI, the amounts that exist in sodas are eight times California’s exposure level (as I reported in my post). If Lee has a gripe with those sources or their logic, let’s here it. But “Nomenclature as indictment”? Wrong.

    3) “Ignoring scale.” Again, no. As I show above, I addressed scale specifically with regard to caramel color. As for aspartame, the whole debate is about scale. The FDA itself acknowledges that aspartame is damaging — but only at super-high intakes. It has a threshold for aspartame consumption — but daily intake even heavy diet drinkers is below that level. Other researchers say the FDA’s threshold is way too high. To engage in this debate is to engage scale.

    4) “Pretending epidemiology hasn’t been invented.” Huh? Again, the first post pointed to an epidemiological study linking diet soda drinkers to strokes; and the second pointed to studies linking them to diabetes and metabolic syndrome. Epidemiology has not been kind to the health outcomes of diet cola consumption — nor was it ignored in my posts. And yes, I took pains to point out that the results were circumstantial.

    As for coffee, the Wikipedia link Lee points us to contains this paragraph:

    Coffee consumption has been shown to have minimal or no impact, positive or negative, on cancer development;[89] however, researchers involved in an ongoing 22-year study by theHarvard School of Public Health state that “the overall balance of risks and benefits [of coffee consumption] are on the side of benefits.”[89] Other studies suggest coffee consumption reduces the risk of being affected by Alzheimer’s disease, Parkinson’s disease, heart disease, diabetes mellitus type 2, cirrhosis of the liver,[90] and gout. A longitudinal study in 2009 showed that those who consumed a moderate amount of coffee or tea (3–5 cups per day) at midlife were less likely to develop dementia and Alzheimer’s disease in late-life compared with those who drank little coffee or avoided it altogether.[91] It increases the risk of acid reflux and associated diseases.[92] Most of coffee’s beneficial effects against type 2 diabetes are not due to its caffeine content, as the positive effects of consumption are greater in those who drink decaffeinated coffee.[93] The presence of antioxidants in coffee has been shown to prevent free radicals from causing cell damage.[94] A recent study showed that roast coffee, high in lipophilic antioxidants and chlorogenic acid lactones, protected primary neuronal cell cultures against hydrogen peroxide-induced cell death.[95]

    Again, compare those results to the — yes — circumstantial epidemiological evidence around diet soda.

    Lee ends by pointing to his own rude health as evidence that everything is fine with the food put out by our giant food corporations: “I mean, I still drink alcohol, and exercise less than I should, and go out in the sun a lot when I’m on vacation. Despite this disregard for my health I am still probably among the healthiest people in history, thanks to having enough money and living in America in the era that I do.”

    I don’t have a glib title for this rhetorical move — the I’m ok, so you’re ok, too, fallacy? — but I invite him to dig into the literature on obesity, diabetes, ADHD, autism, asthma, non-Hodgkin lymphoma, leukemia childhood cancer, cancers of the kidney and renal pelvis, thyroid, pancreas, liver and bile duct, testis, and esophagus. All are on the rise. For the first time in a long time, life expectancy of kid’s today could fall below that of their parents.

  • An interesting discussion, certainly. Tom Lee rightfully points out Tom Philpott’s canned rhetorical devices. Ammonia sounds scary to people who do not have a background in chemistry and may not understand that they are not actually eating ammonia. Countless other things we eat are assembled from compounds that sound bad, and when they don’t, the details can be fudged to make it sound that way. I remember Michael Pollan talking about TBHQ as “a form of butane” and also as “a form of benzene” on two separate occasions. It is neither, although it has a butyl group and a benzene ring, and using that logic you could call butyric acid in Parmesan cheese “a form of butane” and 3 essential amino acids “a form of benzene.” It can be easy to manipulate information about chemistry to make things sound scary.

    And in Tom Philpott’s response, the rhetoric in continued, as he remarks “…that everything is fine with the food put out by our giant food corporations”. A food corporation being giant does not say anything about whether or not the food is healthy – that is a logical fallacy. (Unless you were to assume that no one would ever buy enough healthy food to make a healthy-food company become “giant”.)

    This is a common rhetorical strategy for Tom Philpott – if you don’t have a good argument, just suggest that a large corporation is on the other side. Not too long ago, Tom did it for colony collapse disorder with honeybees:
    “Ridley, a veteran science journalist who calls himself the “rational optimist,” goes on to argue that it could be a virus, and not Bayer CropScience’s highly profitable neonicotinoid pesticides, that’s behind the severe trouble now haunting honeybee populations. His argument seems plausible enough; I am not an entomologist, so I cannot critique it.”

    The fallacious argument is the suggestion that Bayer profiting from neonicotinoid pesticides has anything to with whether or not the pesticide is causing CCD. Nevermind all the research that has been done on several bee viruses and their links to CCD.

    Tom Lee left himself a bit open in this post because he talked more about the flavor of Philpott’s posts, rather than many specifics about the content of the claims. That is easy for Tom Philpott to respond to.

    In contrast, if you point our very specifically that he is dead wrong on something that he believes strongly in, he may ignore you. Back in the fall, I responded to false claims that he made about GE crops, and how he misrepresented even people who he agreed with. (A report called Failure to Yield that concluded that, ironically, GE crops increased corn yields) Tom seemed to have invited the author of that report to argue with me as a proxy, who ended up saying, sheepishly, that yes, I was right, and Tom was wrong, but that Tom accurately reflected the author’s “perspective” on GE crops. Tom even called attention to the discussion in Twitter (as he did with this one), but even after I asked Tom directly, several times to answer my criticisms, he never did. You can see the whole discussion here:

  • Karl. Come on. You guys argued that one into the ground. If 3-4 percent yield gain in corn is all you got after all the billions in research, all the intellectual property pampering, all the regulatory indulgence, all the vast dumpings of Roundup, etc, then, well, whatever. You win. We are going to to find if Monsanto’s products “feed the world” whether we like it or not. The USDA keeps greenlighting them–though the products that get greenlighted tend to be same-ol herbicide tolerant ones. I look forward to nitrogen-use efficiency corn and drought-tolerant corn. Or maybe some corn that can sweep my floor and do my dishes. It really is a wonder technology. Meantime, let’s take this off this cat’s blog. I don’t he wants it clogged up with out old beef.

  • Let yet another Lee weigh in on this. Tom- Thanks for a great post. The only thing that could make it better is a section on heavy metals Kelation.

  • “Karl. Come on. You guys argued that one into the ground.”

    A little statement from you correcting the record goes a long way. I know you want to believe that GE crops don’t work or that it is a one-trick pony that can only help sell herbicides, but maybe a little closer examination would be a good idea. Maybe take a look at the crops excluded from Failure to Yield, such as cotton, canola, papaya, and squash. Maybe look up an intrinsic yield enhancing trait by Mendel Biotechnology that works in soybean and is being tested out in elite bean lines. You mentioned drought-tolerant corn, the trait exists and is being field-tested, along with conventional breeding enhancements. Step outside your comfort zone!

    And maybe take a little time to find out who people are. I don’t work for the biotech industry, nor is my research as a grad student funded by them. You speak about the biotech industry as if I worked for Monsanto, but I do not.

  • I was under the impression that there was more than just the Italian study suggesting adverse health risks, is that the only study? While I would agree that people often freak out about carcinogens they will never encounter in high enough doses to cause cancer, I thought studies showed problems for aspartame at doses that people experience every day?

    I could be wrong, more info please. Not because I personally care for my health, I will cop to a pre existing inclination to ridicule people who drink diet soda, I just want my mocking to be accurate. Goods points about nomenclature, it can be scary, di-hydrogen monoxide in our water? AAAAHH!

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By Tom Lee