Diet Sodas: Adverse Effects of Altered Metabolism, Weight Gain

Professor, Behavioral Neuroscience Department of Psychological Sciences and Ingestive Behavior Research Center Purdue University, 703 Third Street West Lafayette, IN 47907, Interview with:
Susan E. Swithers PhD
Professor, Behavioral Neuroscience
Department of Psychological Sciences and Ingestive Behavior Research Center
Purdue University, 703 Third Street
West Lafayette, IN 47907, USA What are the main findings of the study?

Dr. Swithers: The paper examined the last 5 years of studies that looked at risks associated with consuming artificially sweetened beverages like diet soda. These studies indicated that those who consume diet soda were at significantly greater risk for a variety of negative health outcomes like type 2 diabetes, coronary heart disease, hypertension and stroke, along with being more likely to gain excess weight. These effects might be due to a disruption of basic learned response. ┬áThe idea is that normally things when things that taste sweet are consumed, the body receives calories and sugar. Our bodies can learn to prepare to deal with these calories and this sugar by starting up our digestive processes as soon as the sweet taste hits our mouth, for example by releasing hormones that not only help us regulate blood sugar, but also can contribute to feelings of fullness. When we consume diet sodas, the mouth gets the sweet taste, but the body doesn’t get the calories or the sugar. The body may then learn that a sweet taste in the mouth doesn’t always predict sugar and calories, so it makes adjustments in how many hormones it releases. So when we actually consume real sugar, the body doesn’t produce the same kinds of physiological responses, which can lead to overeating, higher blood sugar, and over the long term could contribute to diseases like diabetes and stroke. Were any of the findings unexpected?

Dr. Swithers: The paper also looked at the risks associated with drinking regular sodas when they were reported along with the diet soda data, and it was somewhat unexpected that the increase in risk for diet soda drinkers was often quite similar to that seen with regular soda drinkers. What should clinicians and patients take away from your report?

Dr. Swithers: Frequent consumption, as little as one every day, of sweetened drinks, whether they regular sodas or diet sodas, is linked to serious health risks. Diabetes, heart disease, metabolic syndrome and stroke all occur at higher rates in people who drink these beverages. This means that people need to be much more mindful when they drink sweetened beverages. They should be viewed as occasional treats, not as normal accompaniments to meals or regular snacks. And people need to pay attention to how much sugar and other sweeteners they are consuming in their overall diet as well, especially if they drink sodas. What recommendations do you have for future research as a result of this study?

Dr. Swithers:We still need to understand what mechanisms are responsible for these observed links between soda intake and negative health outcome. Research looking at whether people who are given unsweetened beverages to consume compared to sweetened beverages have better outcomes is clearly needed, and more research into the basic physiological processes that could connect diet sodas to diseases like diabetes and heart disease might help us come with strategies to potentially prevent or reverse these outcomes.


Trends in Endocrinology & Metabolism
Susan E. Swithers
11 July 2013

Last Updated on November 26, 2014 by Marie Benz MD FAAD