London: Diet drinks may be a wise choice for those who are health conscious, but a new study says that people who guzzle them tend to get fatter than those who take normal full-sugar fizzy drinks.
The 10-year study of almost 500 men and women linked low-calorie soft drinks with bulging waistlines - even when taken in small quantities.
Those who downed two or more diet fizzy drinks a day saw their waistbands expand at five times the rate of those who never touched the stuff, according to researchers at the University of Texas.
Prof Helen Hazuda, who led the study, said diet sodas and artificial sweeteners may foster a sweet tooth, distort appetite and even damage key brain cells. So, treating them as healthy alternatives may be "ill advised".
She added: "They may be free of calories but not of consequences."
For the study, the researchers tracked the health and habits of 474 adults for an average of nine and a half years. They then compared growth in waistline of those who consumed diet drinks with others including some who buy fizzy drinks.
Overall, those who favoured diet drinks saw their waists expand 70 per cent faster. But "frequent users" - defined as those who drink two or more cans a day - saw a 500 per cent greater increase in girth.

Significantly, the results still stood even when other factors such as exercise, social class, education and smoking were taken into account, the American Diabetes Association conference heard.
"These results suggest that amidst the national drive to reduce chronic consumption of sugar-sweetened drinks, policies that would promote consumption of diet soft drinks may have unintended deleterious side-effects," Hazuda said.
A related second study, involving some of the same researchers and carried out on mice, linked sweetener aspartame with the sort of damage in the pancreas that can occur early in diabetes.
The researchers said they think artificial sweeteners may distort appetite, leaving us craving extra-sweet and unhealthy treats. They may also damage brain cells involved in feelings of fullness, while the lack of real sugar could also stop us from feeling full.
Sharon Fowler, who was involved in both pieces of research said, "Artificial sweeteners could have the effect of triggering appetite but unlike regular sugars they don't deliver something that will squelch the appetite."