A recent study out of the University of Texas Health Science Center may have left a few people scratching their heads in puzzlement. It showed that people who drink diet sodas were more likely to become overweight than those who didn’t. And the more diet sodas you drink, the fatter you’re likely to be.
How does that work? Actually, it’s a good example of correlation, not causality. The study was conducted by examining questionnaires and medical records of over 1,000 people. It showed that the heavier folks tended to be the ones who drank the most diet soda. That doesn’t prove that diet soda causes the weight gain; it just shows that when you see one (diet sodas), you likely see the other (higher weights).
This is an important distinction because research correlations are frequently but mistakenly assumed to be proof of cause and effect. For example, one of the bigger arguments today in ‘weight’ circles is whether health problems like high blood pressure and diabetes are unavoidable consequences of obesity. Said another way, there are people who are classified as obese according to the charts, yet they live healthy lifestyles and show it in terms of all health parameters except their weight. Which is what the argument centers on. If these healthy folks are also fat, then can weight be accurately considered an independent indicator of health? It can, according to those who incorrectly cite correlational studies as the proof. But when you look at healthy fat folks, you see there’s something else in play that correlational studies can’t account for – there has to be another causal factor.
Anyway, back to the diet sodas.
My personal take on this is that this correlation suggests something I’ve long noticed about the eating habits of many people who struggle with their weight. They suck! That is, they don’t eat well – they skip meals, they try to keep calories to a minimum, they’re constantly worrying about eating too much. So when hunger attacks, what do they turn to? Something calorie free that will hopefully turn their hunger down a notch. Things like black coffee and diet soda seem to do that fairly well…for a while. But then the hunger wins; good intentions for eating lightly go out the window in the face of extreme hunger. Even if someone can manage to keep calorie intake low, they toy with reducing their metabolic rate, which then makes it even easier to gain weight.
The last thing any of us who have struggled with weight needs is another food fear. I strongly doubt that there’s anything inherently wrong with diet sodas that cause people to gain weight. Instead, I think it’s how we use the sodas that’s the problem.