From the responses I've seen so far, my reflection is as follows:
You can moderate your behavior to reasonably mitigate the possible risks of certain substances as much as you feel is prudent give the relative certainty and severity of the risks;
Or you can develop an ill-informed, hyperbolic, almost knee-jerk reaction to the risks and cast aspersions toward the people who shrug and either suggest all things in moderation, or suggest the risks aren't that high. It is not obvious to me that these people are either irresponsible or brain-damaged. It is just as possible they performed a rational risk assessment and arrived at a different conclusion. It's something to be discussed, not to be worked up into a religious fervor over.
For example, from the comments herein, diet colas do not promote tooth decay, nor do they promote diabetes. In fact, they are considered safe for diabetic people to drink. They contain no sucrose, nor any HFCS. They contain aspartame, an alternative sweetener with entirely different properties. They contain carbonated water, but as I cited elsewhere, carbonated water is not that conducive to tooth decay.
The study isn't even conclusive yet, and the article hedges this by saying it can cause muscle weakness, not that it will. The article mentions two people, and declare that the results can be generalized, because the investigators believe they can. They present this along with some scary statistics to assure us that, if the results can be generalized, we're all in peril.
2-3 liters sounds like a lot, but it is only because we've assumed a priori the certain risk of ingesting these substances, and declare the only proper amount for assuring ones health is 0 liters per day, with no variance. If the average were half that, aspersions would likely still be cast.
I'm pretty brain damaged I guess. I must drink at least a 3 liter bottle of diet Coke a day, probably more. I've tried stopping at various times and it's not easy; it's a somewhat more serious addiction than a lot of people might believe, imho. The best luck I've had was with drinking coffee for the caffeine and club soda for the bubbly sensation (not simultaneously), and I managed to get away from it for a month, but I've since lapsed. Will try again upon reading this article.
Coffee can have its own issues; I've found tea (green or black, hot or cold) and carbonated water the easiest glide-path down from periods of cola and coffee overconsumption.
Diet sodas contain aspartame, which does not promote tooth decay. A google search will produce a number of results, with varying degrees of motivation to market aspartame, all saying pretty much the same thing.
For carbonated beverages in general, the concern appears to be more about the acids in the substance than in the carbonation, at least as my limited research suggests. Some of these same acids occur in a variety of other foods as well (citric acid in citrus fruits, for instance.) Others, like phosphoric acid, which has been correlated to decreased bone density in some studies, are only in certain soft drinks. Even then, the risk is not certain.
I wish there was a low/no calorie sweetener that was actually safe to use. Aspartame is a carcinogen, as are most other artificial sweeteners...even Splenda contains chlorine. Aspartame also gives me migraines, so I generally stick with cane sugar or honey. Stevia, xylitol, and erythyritol have many positives, but they're pricey and often have a bad aftertaste and/or laxative effect. I'm addicted to sweet tea, but I'm trying to reduce my sugar consumption. White and green tea and fruit spritzers are the only alternatives I've found that work for me...black tea just makes me crave sugar.
Municipal tap water often has chlorine, too. I'm not sure how much, and water varies from city to city, but there's often enough to affect bread rising, so it's not a completely trivial amount. At the same time, anything that gets added to tap water (to discourage micro-organisms, which of course includes yeast) is probably reasonably harmless in small quantities.
As sweeteners (both artificial and real) go, I doubt there's going to be a clear view of their pros and cons in the near future -- there's way, way too much money involved. (I like honey and vanilla sugar, but try to not use too much.)
If my teeth aren't rotting (they're not) and I'm not getting fat (I'm not) then why shouldn't I? (I do.) It wasn't exactly obvious to me that it would be depleting my potassium levels. :)
My wife works in the medical field, and she deals with many diabetic patients. Until recently, I underestimated how horrible this disease can actually be. I knew it could be serious, but I mainly just thought about people having to watch what they eat and having to monitor their blood sugar levels.
Seeing the photos of the huge, oozing wounds that never heal and hearing the stories about renal failure, blindness, and amputations have certainly made me more aware of my diet. Eating one large, high GI meal per day (as I used to do) is basically a ticket to diabetes (and probably Alzheimers, which many researchers are arguing is essentially just another type of diabetes.) I now eat 5-6 smaller meals per day, and I try to balance them and monitor the GI load. There are new studies that indicate that you can do permanent damage to your brain by eating large, sugary meals even BEFORE you have any indication that you are doing so. Some people have damaged their brains even before they register as pre-diabetic on blood tests.
The problem seems to be the fructose, corn syrup, and caffeine, not the actual "soda."
I drink a brand called Diet Rite which is made with Splenda and has no caffeine or sodium. And, actually, I honestly like the taste of it better than Coke or Pepsi.
I think something like that is fine and if the other soda companies switched to healthier ingredients they would be fine too.
My in-laws drink Diet Rite and Vernor's Ginger Ale. Unfortunately, Splenda is not as safe as they make it out to be...it has chlorine in it. Chlorine is a carcinogen.
When I see cans of Java Monster (an energy drink), I picture some junior programmer on an all-nighter, all hopped up on caffeine and copy-and-pasting more code than most people produce in a year. "Oh no! Our codebase got hit by a Java Monster last night!"
i have no access to the details (would have to pay, not a student with a univ license or anything...), so if someone does have access - it'd be nice to know at which amount in this study one transitions from 'moderate' to 'heavy.' 5 is apparently heavy, but where is 2 cans?
there's nothing new here - no new research - it's just an editorial. don't drink too much soda - duh. i was hoping they figured could narrow down what moderate means.
My same disappointment with the "journalistic" coverage applies now:
They don't seem to differentiate colas from other sodas. A surprise to me, since I seem to recall hearing the high phosphorous content of colas can compete with some other mineral absorption (calcium, was it?) ...maybe compete with potassium?
Personally, I've felt better about my physical stamina when I surrender to my crave for a "fizzling" drink by going to some diet lemon-lime (no caffeine or sugar) rather than a "cola" (whether caffeinated or sugared). YMMV
Wow. I was worried that 40oz might be rotting my body, but 2-3 liters is a lot of soda. Overuse of most products will have poor health effects.