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Is diet soda making you fat?

Diet soda on the shelf

The diet soda controversy is still raging on, study after study has been coming in saying that it helps weight loss, it hurts weight loss, and frankly it can all be a little confusing. Well this probably won’t help matters any, a new study shows that increasing diet soda intake is directly linked to greater abdominal obesity in adults 65 years of age and older. These findings raise concerns about the safety of chronic diet soda consumption, which may increase belly fat and contribute to greater risk of metabolic syndrome and cardiovascular diseases.

Metabolic syndrome –a combination of risk factors that may lead to high blood pressure, diabetes, heart disease, and stroke–is one of the results of the obesity epidemic. 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.

In an effort to combat obesity, many adults try to reduce sugar intake by turning to non-nutritive or artificial sweeteners, such as aspartame, saccharin, or sucralose. Previous research shows that in the past 30 years, artificial sweeteners and diet soda intake have increased, yet the prevalence of obesity has also seen a dramatic increase in the same time period. Many of the studies exploring diet soda consumption and cardiometabolic diseases have focused on middle-aged and younger adults.

“Our 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,” explains lead author Sharon Fowler, MPH, from the University of Texas Health Science Center at San Antonio.

“The burden of metabolic syndrome and cardiovascular disease, along with healthcare costs, is great in the ever-increasing senior population.”

The San Antonio Longitudinal Study of Aging (SALSA) enrolled 749 hispanic and European Americans who were aged 65 and older at the start of the study (1992-96). Diet soda intake, waist circumference, height, and weight were measured at study onset, and at three follow-ups in 2000-01, 2001-03, and 2003-04, for a total of 9.4 follow-up years. At the first follow-up there were 474 (79.1%) surviving participants; there were 413 (73.4%) at the second follow-up and 375 (71.0%) at the third follow-up.

Findings indicate that the increase in waist circumference among diet soda drinkers, per follow-up interval, was almost triple that among non-users: 2.11 cm versus 0.77 cm, respectively. After adjustment for multiple potential confounders, interval waist circumference increases were 0.77 cm for non-users, 1.76 cm for occasional users, and 3.04 cm for daily users. This translates to waist circumference increases of 0.80 inches for non-users, 1.83 inches for occasional users, and 3.16 inches for daily users over the total 9.4-year follow-up period.

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

The authors recommend that older individuals who drink diet soda daily, particularly those at high cardiometabolic risk, should try to curb their consumption of artificially sweetened drinks. The research does have it’s limitations, it only draws a connection between diet soda consumption and fat increase around the waist. It does not offer a biological or psychological explanation for the cause behind the weight gain, only the correlation between diet soda and that gain.

There are known psychological reasons for instance, which could account for this. For example, the positivity effect, which is more prevalent in older adults. The positivity effect is when we see a good choice, decision or news as having more weight than a bad one. For instance, someone who deals with this might feel that the $50 dollars they saved for retirement was better than the $100 they used for a impulse purchase. Similarly when you are dieting you could use that diet soda as justification for some chocolate cake. It would then stand to reason that more diet soda would lead to a more relaxed perception regarding a diet.

However, I should also admit that this is all just speculation and more research would have to be done to find the real cause. Until then, if you are older and trying to watch your weight, you may want to pass on that diet soda and go for the water instead. Though to be safe, you may want to avoid thinking too highly of that choice.

Fowler, S., Williams, K., & Hazuda, H. (2015). Diet Soda Intake Is Associated with Long-Term Increases in Waist Circumference in a Biethnic Cohort of Older Adults: The San Antonio Longitudinal Study of Aging Journal of the American Geriatrics Society DOI: 10.1111/jgs.13376

2 responses

  1. Nezza Villanueva

    I think that sodas in general whether it maybe diet or non diet are factors that contribute to an unhealthy diet. An important advice is to reduce or eliminate the intake of soft drinks. People who consume at least one soft drink per day are more likely than others to be overweight, and if they are not already overweight, they are more likely than others to become overweight. Companies began sweetening their beverages with high fructose corn syrup instead of sugar. Fructose is somewhat sweeter than common table sugar and the hope was that could satisfy their craving for sweets without quite as many calories. But this idea did not work for obesity has become more common and fructose increases this problem. Diet beverages are known to be ineffective, for consumption of sugar has also increased because many people seem to drink diet drinks in addition to their usual sugar intake thinking that by drinking diet drinks it will lower their sugar intake. Reality is people should learn how to limit or lessen their soda intake for such substance can definitely have its affect on our bodies.


    April 16, 2015 at 9:46 pm

    • Well the more common theory about diet soda is that people overly weigh good choices when compared to bad choices (ie drinking a diet soda is better so that piece of chocolate cake is okay). Sugar is sugar and I doubt that the introduction of HFCS (when compared to say table sugar) changed anything in regards to obesity. Frankly there are probably one too many factors involved to throw a label on it. I think people should try to lower their soda or just sugar intake in general as well, but I don’t think eliminating sugary sodas from popular consumption would drastically alter the obesity epidemic we have going on.


      April 19, 2015 at 10:28 am

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