One study came to a surprising conclusion—diet fizzy drinks with no added sugars were associated with larger waistlines. Published in the Journal of the American Geriatrics Society, the study looked at data from 749 Mexican-American and European-American people, over the age of 65, who originally participated in the San Antonio Longitudinal Study of Aging between 1992 and 1996. After adjusting for factors such as demographic information, level of physical activity, presence of diabetes, and smoking, researchers found that:

• People who drank diet fizzy drink daily added around 3.04 cm to their waistlines; people who occasionally drank diet fizzy drink added 1.76 cm to their waistlines; and people who did not drink diet fizzy drink added only 0.77 cm to their waistlines.
• In contrast, drinks with added sugars were not associated with waistlines.

However, this study may not be the final word on this matter. In fact, there are at least two other possible ways to explain the findings. One potential explanation is that people who are already overweight might tend to drink more diet drinks to prevent further weight gain; the other explanation is that people who drink diet fizzy drink might think that they are saving calories and so over-consume other types of foods and drinks. While other research does indicate that artificial sweeteners could disrupt healthy metabolisms, more evidence is needed to confirm the results of this study.