You would think that going on a "diet" would help trim your waistline, but when it comes to diet soda, it's actually found to be linked to greater belly fat in adults 65 years of age and older.

What's more, the study found that the more diet soda someone drank, the more likely they were to add to their waistline.

Abdominal obesity could possibly lead to cardiovascular diseases and metabolic syndrome - a combination of risk factors that may lead to high blood pressure, diabetes, heart disease, and stroke. And with the obesity epidemic running rampant, the risk of developing these conditions is cause for concern.

In fact, the World Health Organization (WHO) estimates that 1.9 billion adults were overweight (body mass index [BMI] of 25 or more) in 2014. Of this group, 600 million people fell into the obese range (BMI of 30 or more) - a figure that has more than doubled since 1980.

Sugary beverages are often cited as main contributors to obesity, so in an effort to curb weight gain, many adults will turn to nonnutritive or artificial sweeteners - such as aspartame, saccharin, or sucralose - to reduce sugar intake.

"They feel like they're protected against eating too many calories," lead author Sharon Fowler, from the University of Texas Health Science Center at San Antonio, told CBS News.

Consequentially, over the past 30 years more and more people have started using artificial sweeteners and drinking diet soda; and yet, at the same time the prevalence of obesity has dramatically increased.

Previous studies have mostly focused on how diet soda impacts middle-aged and younger adults in terms of weight gain, but this "study seeks to fill the age gap by exploring the adverse health effects of diet soda intake in individuals 65 years of age and older," Fowler said in a press release.

"The burden of metabolic syndrome and cardiovascular disease, along with healthcare costs, is great in the ever-increasing senior population," she added. (Scroll to read on...)

The research looked at previous findings from the San Antonio Longitudinal Study of Aging (SALSA), a 10-year study that involved 749 Mexican- and European-Americans aged 65 and older. They measured diet soda intake, waist circumference, height, and weight, both before the study and during three follow-ups.

At the first follow-up there were 474 (79.1%) surviving participants, 413 (73.4%) at the second follow-up and 375 (71.0%) at the third follow-up.

In addition, the researchers found that the waistlines of people who never drank diet sodas increased by 0.8 inches for the length of the study. By comparison, occasional diet soda drinkers saw their waistlines grow by 1.8 inches, whereas those who consumed the drinks every day ballooned by more than 3 inches, according to the study.

While this study did find a link between the consumption of diet sodas and a wider waist circumference, it did not establish a cause-and-effect relationship.

"The SALSA study shows that increasing diet soda intake was associated with escalating abdominal obesity, which may increase cardiometabolic risk in older adults," Fowler concluded.

So predictably, the research team recommends older adults, particularly those at high cardiometabolic risk, try to avoid quenching their thirst with diet soda on a daily basis. Instead, opt for fresh-brewed tea and coffee (if you need a caffeine fix), or bubbly unsweetened mineral water.

The results were published in the Journal of the American Geriatrics Society.
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