User Query: Diet soft drinks – friend or foe?

One of our readers approached me the other day with the following not-quite-a-question:

I’d like to see you guys do something on Diet Coke. I am [probably] not alone as someone who finds it MUCH harder to lose weight when drinking [it].  I’ll bet it has to do with blood sugar and insulin responsiveness.

A moment of full disclosure here: I used to work for Coca-Cola North America (Coke’s bottling and distribution subsidiary). Personally, I prefer Pepsi. I seldom have soft drinks at all these days, but prefer regular to unleaded on the rare occasions I do partake. Those items notwithstanding, I’m going to more generally address the topic as it pertains to diet soft drinks in general, rather than focus attention on one particular brand or flavor.

So, back to the subject at hand:

Do these no-calorie drinks hamper weight loss? If so, how?

As Deep Thought said, “Hmm. Tricky.”

Let’s start with what is widely cited as the definitive research on the topic, a study conducted by the Health Services Center at the University of Texas:

At least daily consumption of diet soda was associated with a 36% greater relative risk of incident metabolic syndrome and a 67% greater relative risk of incident type 2 diabetes compared with nonconsumption. Although these observational data cannot establish causality, consumption of diet soda at least daily was associated with significantly greater risks of select incident metabolic syndrome components and type 2 diabetes.

In plain English? “People who drink diet soda are more likely to exhibit signs of a troubled metabolism, and are much more likely to have type 2 diabetes than those who don’t drink it.” The authors explicitly state that they weren’t able to determine a causal relationship — ie: “drinking diet soda makes you gain weight and puts you at risk for type 2 diabetes” — but they did establish a strong correlation over the period of years during which their research was conducted.

Compared to folks who never drink diet soft drinks, the risk of type 2 diabetes increased by:

• 25% for people that drank one or more servings per week, but less than one serving per day
• 38% for people that drank one or more servings per day

Okay, that’s not exactly music to the ears of the diet soft drink aficionados in the audience.  There are a lot of possibilities here — the folks who drink diet soda may be doing so to help stave off other weight and health-related issues, but since they’re predisposed towards having them, it’s simply not enough by itself (remember, if you drink a case of pop a week, switching from regular to diet and making no other changes, you should theoretically lose about a pound a week, since that’s roughly the number of calories you’re avoiding).

However, it gets worse.

There was a 41 percent increase in risk of being overweight for every can or bottle of diet soft drink a person consumes each day….  What we saw was that the more diet sodas a person drinks, the more weight they’re likely to gain.

– Sharon P. Fowler and colleagues; University of Texas Health Science Center at San Antonio

That, on the other hand, is about as subtle as a rail gun round to the sternum.

One possible explanation is that, because someone has made the switch to diet soda, they may make up those calories elsewhere (and not in a healthy manner). “Hey, I can have the medium order of fries, since I’m drinking a diet cola.”

/facepalm

While this is almost certainly true in some cases, it’s probably not enough to account for the statistics the UT studies revealed. One other hypothesis that has been suggested, but not yet supported (or negated) through research, is that the consumption of the sweetened beverage causes our endocrine system to issue an all-hands alert for insulin production, with the expectation that there’s going to be a flood of sugars to the bloodstream — until the 1960′s, with the introduction of Tab, anything that sweet was an immediate source of simple sugars; fifty years isn’t enough time to adapt. There may be additional triggers — things that signal satiety (feelings of being full) don’t get tripped by the lack of calories, so you’ll still eat just as much, even on top of a can or two of diet soda.

A similar theory is more psychological, in the Pavlovian sense — we’ve grown so accustomed to drinking these HFCS-infused beverages (and this includes bottled fruit juices, sports drinks, and a whole raft of stuff… even ketchup), so when we taste one, our body does the same thing as it would with a regular soft drink (ie: produce insulin).

No matter what the underlying reason is for this state of affairs, there are so many other chemicals and artificial sweeteners in diet soda that giving them up is probably not a bad idea anyhow, even though research has shown that aspartame, acesulfame potassium (ace-K), sucralose (Splenda), and even bad old saccharine are, in any quantity you’re capable of ingesting, non-toxic. Whether they can be considered Mostly Harmless is another matter altogether.

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3. User Queries: Alli Alli oxen-free?