Several studies have linked soda drinking–including diet soda– with diabetes and metabolic syndrome, a series of conditions such as obesity, high cholesterol, and high blood pressure.
According to the American Heart Association, people with metabolic syndrome are at increased risk of coronary heart disease and other diseases related to plaque buildups in artery walls.
One of the most recent studies was unique in that it included a large populations–about 6,000 individuals who were part of the Framingham Heart Study that has been following patients since 1948 in the town of Framingham, MA.
Journal of the American Medical Association (JAMA. 2004;292:927-934)
Circulation, July 24, 2007