After following the lives of almost 500 older adults for several years, researchers found that increasing diet soda consumption is linked to escalating abdominal obesity. According to the study, those who drank diet soda every day experienced an increase in waist circumference that was three times greater than those who did not consume such beverages. The more diet soda people drank, the more belly fat they gained.
While the study can’t prove that diet sodas were the cause of these expanding waistlines, the researchers suggest that older individuals should probably think about trading in these beverages for things like unsweetened tea and coffee, or plain and simple water. The findings have been published in the Journal of the American Geriatrics Society.
The rising obesity epidemic is a serious global public health concern. According to the WHO, close to 2 billion individuals were overweight last year, 600 million of whom were obese. Being overweight or obese are both risk factors for a number of chronic conditions, such as diabetes, cardiovascular diseases and even cancer.
Since obesity is preventable, many attempt to tackle it through a reduction in calorie intake by means of consuming sugar-free products artificially sweetened with things like aspartame or saccharin, such as diet coke. But while the intake of these products has increased, so has obesity, spurring researchers to investigate whether they are an effective, or even safe, weight loss aid. And these studies have produced a mix bag of results, to say the least.
Some long-term studies have suggested that regularly consuming diet sodas reduces calorie intake and promotes weight loss, but others have shown they do nothing and some even found they were associated with weight gain. Several scientists hypothesized that artificial sweeteners could be increasing our appetite, especially for sugary foods, and hence promote weight gain, but one (industry-funded) study concluded that diet beverages do not in fact increase appetite.
It’s clear that the literature is confusing, but an apparent gap that scientists noticed is a lack of studies investigating the effects of diet drinks in those aged 65 or older, which is important given the fact that the global population is aging. Researchers from the University of Texas HSC therefore decided to attempt to fill in this gap and designed a study that set out to investigate almost 750 Mexican- and European-Americans over the course of a decade, all of whom were 65 or older at the start. Due to drop outs, only 466 were included in the analysis, which is a fairly modest number.
Participants were categorized into three groups dependent on how much diet soda they drank: non-users, occasional users (less than one per day) and daily users. At the outset of the study, and then twice more, the researchers measured the participants’ height, weight and waist circumference (WC), which is an indicator of abdominal fat. After adjusting for initial WC, exercise, smoking and diabetes, researchers observed a dose-response relationship with average WC increases of 0.8 inches (2 cm) for non-users, 1.83 inches (4.6 cm) for occasional drinkers and 3.16 inches (8 cm) for daily users.
While the study is interesting, it is important to note that it has limitations. Associations cannot prove cause and effect, and it failed to take into account complete dietary intake, which rings alarm bells. Furthermore, it is unclear how the drinks could be possibly causing people’s waistlines to expand, although a recent study in mice offered a possible explanation with the finding that artificial sweeteners can alter gut microbe composition and promote metabolic abnormalities.