It goes something like this: a customer of some—shall we say, considerable carriage--comes up to the counter. He or she orders a fried chicken sandwich or two, often with cheese, a large order of fries, a cup of cole slaw (~30% mayonnaise by volume), and a 32-oz—wait for it--diet soda.
Now, far be it from me to extol the virtues of high-fructose corn syrup, the consumption of which (in quantity) has been linked to elevated levels of ureic acid in the blood which definitely leads to kidney stones and may (there is mounting evidence) be linked to cardiovascular disease. (All of this is in addition to the problems associated with consuming such concentrated calories in the form of simple carbohydrates; i.e., elevated blood sugar, insulin resistance, and weight gain.) However, even if you assume that our corpulent customer is making a one-to-one substitution of diet soda for leaded—and I’m not sure we should assume that; more on that below--the caloric savings is clearly not enough of an offset to make a difference. S/he’s still fat.
Now I realize I’ve given you an anecdote here, and that you have to trust me (and my memory some 14 years out) when I say that this customer was not exceptional but in fact typical—an overweight customer eating a large amount of food and washing it down with diet soda. And even if I had hard data to support my more general assertion that the habitual consumer of diet soda is, on average, overweight to obese, you could still argue that this is a matter of which comes first: the (deep-fried) chicken or the (4-)egg (Denver omelet)? More to the point, do people drink diet soda because they’re fat (and don’t want to be), or is the diet soda making/keeping them fat?
While the first option is appealing in its simplicity, I think that the second bears careful consideration. So, too, do the authors of an upcoming paper in Behavioral Neuroscience discussed briefly by Art de Vany here.
The rats who ate artificially sweetened yogurt consumed more food overall and gained more weight. The body temperatures of those rats also didn’t rise as high as the others. “That might be a kind of measure of energy expenditure, suggesting not only are the animals eating more calories, they may be expending or burning up fewer calories,” Swithers said.
I haven’t been able to pull up the paper yet [Ed.--here it is], but as Dr. de Vany points out, this sounds like artificial sweetener may be tricking out the satiety centers of the hypothalamus, causing a release of insulin in advance of a blood glucose spike that doesn’t come…with the net effect of causing blood sugar to fall precipitously, stimulating hunger. Couple that to a change in thermoregulation (which may or may not be directly related, but in the rats certainly seems to be happening) and you are set up for weight gain.
My personal prejudice is that I am against “fake food” in all its forms. I won’t eat anything with artificial sweetener in it on purpose—not only because I think these are chemicals for which we have absolutely no metabolic adaptations, but because they taste awful. Reduced fat dairy is OK for cooking some things—even though I generally hate it—as long as there is nothing synthetic put in to “replace” the fat. Don’t even get me started on soy products—after trying out soy milk a few years ago, I found myself with an odd craving for the stuff and eventually developed what I am 90% certain is a mild allergy to it, and only “mild” because I quit drinking it the moment I made the connection.
But beyond all of that, I have generally found that “diet food” is tremendously unsatisfying, I think in no small part because it contains less of the natural components of food (protein, fat, sugar) that signal to your brain that you have eaten. My guess is that people tend to eat more of it, or just more of everything, as a result. However, if this study translates to humans at all, the situation might be much, much worse than that.
I also wonder the extent to which this may be related to the phenomenon that many people report upon reducing the amount of sugar and starch in their diet; namely, the less of it you consume, the more you lose your taste for it. I can definitely vouch for this—I almost never drink soda any more, and generally regret it if I do. I find orange and other fruit juices unbearably sweet. I’m pretty much done with pasta. The only candy I like is chocolate—the more bitter, the better. [m], who bakes all the time, is constantly cutting the sugar down (not replacing it) in her recipes, and we both tend to like the result much better than if she’d followed the recipe exactly. If instead of reducing sugar in your diet, you are replacing it with a hyper-sweet synthetic, you probably aren’t benefiting from losing your taste for sugar.
The take-home message here, as far as I am concerned, is ditch the fake food. Eat well…and less.
