Is Diet Soda Making You Fat?

Switching to calorie-free, artificially-sweetened diet soda may seem like a smart choice if you are trying to lose weight or avoid weight gain, but it turns out that diet soda may not be the best option for your waist line. Here, you will learn what the research says about the relationship between diet soda and weight.  

Short-Term Impact of Diet Drinks

In as little as one year, diet soda can have an impact on your weight. A 1986 study in Preventive Medicine followed women for one year and tracked their weight changes.   Results showed that women who consumed artificial sweeteners were significantly more likely to gain weight than were women who did not consume them. Study authors concluded that their research did not support the belief that artificial sweeteners can aid weight loss or prevent weight gain.

In a shorter-term animal study, published in a 2007 edition of Appetite, researchers compared rats given artificial sweeteners to rats given the caloric sweeteners, glucose and sucrose.  During the two-week study period, rats given the artificial sweeteners consumed more calories and gained more weight than rats given the caloric sweeteners.

The Long-Term Effects of Diet Soda

After years of drinking diet soda, you may find yourself packing on the pounds. In a 2008 study in the journal Obesity, researchers followed participants for a period of 7-8 years, measuring their weight and diet soda consumption.   They found that compared to those who drank no diet soda, those who consumed more than 21 diet beverages per week nearly doubled their risk of becoming overweight or obese during the study period, even if they were at a normal weight at the beginning of the study.  Furthermore, study participants who consumed diet beverages gained 47 percent more weight during the study period than did those who did not consume diet beverages.

A 2009 study in Diabetes Care painted a similar picture.   Researchers followed study participants for five years and found that those who consumed at least one diet soda per day were at increased risk of developing large waist sizes during the study period.  So, contrary to popular belief, sipping on diet drinks may not be the best way to shrink your waistline.

Reasons for the Association between Diet Soda and Weight Gain

With research showing a link between diet soda and weight gain, scientists have begun to explore the reasons for this association.   Researchers for a 2012 edition of Physiology & Behavior performed an MRI on study participants and found that those who consumed diet soda showed increased responses to sweet tastes in areas of the brain associated with rewards and pleasure.  The researchers concluded that those who regularly drink diet soda experience changes in their response to sweet tastes, which could explain the relationship between diet soda and obesity.

Additional research has found that diet beverages may change our food choices in a way that can increase the risk of weight gain.   In a 2014 study in the journal Appetite, participants who were given Sprite Zero, a diet beverage, were nearly three times as likely to take candy that was offered to them as were participants who were given regular Sprite or mineral water.   In a separate part of the study, participants who consumed the Sprite Zero felt less satisfied after eating cookies than those who drank the regular Sprite or mineral water.  According to this research, diet soda may make you more likely to succumb to cravings and less likely to be satisfied with your food. Over time, this could certainly cause weight gain.

With the research supporting a relationship between diet soda and weight gain, it may be time to cut this type of beverage out of your diet. Stick to water or unsweetened teas to help you manage your weight.


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