Diet sodas won’t help you lose weight. In fact, they may actually make you gain weight, according to a meta-study which looks at historic data on weight and low-calorie sweetener use. The results strongly suggest that diet drinks are no better than sugary drinks when it comes to managing weight. That is, a diet cola is just as bad as a regular cola.
The research, from the National Institute on Aging, and the National Institutes of Health in Baltimore, looked at data from the Baltimore Longitudinal Study of Aging, going back as far as 1984, and including 1,454 participants. By comparing their various body measurements and obesity levels with their consumption of diet sodas, the research were able to tease out a correlation after correcting for many dietary and other factors like smoking, exercise, ethnicity, and so on.
“Low-calorie sweetener use,” concludes the study, “is independently associated with heavier relative weight, a larger waist, and a higher prevalence and incidence of abdominal obesity suggesting that low-calorie sweetener use may not be an effective means of weight control.”
While short-term studies on the effects of diet soda have been inconclusive, this new study agrees with a 2011 study from the University of Texas, which also looked at soda use over 10 years. “Diet soda drinkers saw a 70% increase in waist circumference compared with non-drinkers over the course of a decade,” wrote we wrote at the time. “People who drank more than two diet sodas a day saw a staggering 500% greater waist circumference compared to non-drinkers.”
Why? That part, science is less clear about. It could be that the sweeteners affect your gut flora. It could be that they make you crave more sweet things–and not all the sweet things you eat are sugar-free. It could even be that the artificial sweeteners still trigger the same response in your body as real sugar. But given that this shows just how pointless “diet” drinks are in controlling weight, if you’re only going to drink the rare soda, make it a real one. But it seems like we have to ditch sweetened beverages altogether, or be doomed to a lifetime of obesity.