When I was director of the Congressional Budget Office, I was testifying so frequently to the Senate Finance Committee that the chairman granted me a special exception to the committee rules: He allowed me to drink diet soda rather than just water during hearings. At my peak, I was downing up to eight diet sodas a day.
My family did not think this was such a great idea, and at their urging I have largely eliminated my diet soda drinking. Recent data from Beverage Digest suggest others are cutting back also; consumption of diet sodas fell more than that of sugary sodas in 2013. "While the health risks of sugary sodas have been publicized for some time, the growing public aversion to diet drinks — with many believing artificial sweeteners are also unhealthy — has caught the industry somewhat off guard," the Wall Street Journal noted.
This raises two questions: Why is total consumption declining, and is drinking diet soda harmful to health? Although the data do suggest a change in attitudes toward diet sodas, one potentially underappreciated factor in the consumption data is the role of demographics. Consumption of diet soda is twice as high among non-Hispanic whites as among Hispanics, for example, as data from the National Center for Health Statistics show. As the share of non-Hispanic whites in the population declines and the share of Hispanics rises, one would expect diet soda consumption per person to fall.
Demographic shifts don't entirely explain the shift in soda drinking, however. Concern about health effects appears to be rising, too — which is not surprising, given how much media attention has been trained on reports of harm.
A recent example is an analysis of the extent to which the consumption of diet drinks influences cardiovascular events — a study that highlights both the insights and the shortcomings of research on diet soda. Ankur Vyas and colleagues at the University of Iowa examined the diet drink consumption of almost 60,000 older women and concluded that, "compared to women who never or only rarely consume diet drinks, those who consumed two or more a day were 30 percent more likely to suffer a cardiovascular event and 50 percent more likely to die from related disease."