Does Diet Soda Slow the Metabolism?

The scientific jury is still out on the health effects of drinking diet soda. Some recent research has found that artificial sweeteners like those used in diet soda actually fuel weight gain and may even promote metabolic disturbances that increase your risk for Type 2 diabetes. In contrast, a 2014 analysis of research findings concluded that low- and no-calorie sweeteners do in fact assist with moderate weight loss. As a compromise, Charlie Seltzer, M.D., writing on The Huffington Post, suggests drinking diet soda only in moderation and carefully monitoring how drinking it affects your metabolism and weight.

Weight Gain Findings

The Food and Research Action Center reports that obesity rates for U.S. adults and children are more than double what they were in the 1970s. It's little wonder that researchers have increasingly sought out the root causes of the epidemic. The results of a large study, published in the journal “Obesity” in 2008, looked at diet soda drinking over an eight-year period among adults in San Antonio, Texas. Researchers found that people who drank 21 or more servings of diet soda weekly doubled their risk of obesity. In the study, diet soda drinkers had body mass indexes 47 percent higher than those of participants who drank no diet soda at all.

Evidence of Metabolic Disturbance

Artificial sweeteners may taste up to 20,000 times sweeter than regular sugar, reports an article on the New Scientist website. When you eat artificial sweeteners, your body may get confused and release too much insulin to process the substances, and these hormonal disruptions may in turn lead to overeating, Susan Swithers, a Purdue University professor, told NPR in 2013. According to a study published in “Nature” in 2014, this metabolic disruption may lead to Type 2 diabetes. In a 2014 study of more than 66,000 women, drinking beverages containing either artificial sweeteners or regular sugar led to increased risk for diabetes. The results were published in the “American Journal of Clinical Nutrition.”

Weight Loss Still Possible

In 2014, the “American Journal of Clinical Nutrition” published a meta-analysis -- an examination of a range of research studies -- stating that it's possible to lose weight by consuming artificial sweeteners in food or beverages. The analysis looked at a total of 15 clinical trials and nine cohort studies. Findings indicated that substituting artificially sweetened products for higher-calorie counterparts, like sugar-sweetened drinks, did not lead to increased weight or fat mass, and in the clinical trials it actually resulted in “modest” weight loss.

Monitoring Diet Soda Intake

Because research results conflict, drinking diet soda may have different effects on different people. If you find that drinking it causes you to eat more, Seltzer recommends totally eliminating diet soda from your regimen. Other people may drink fewer diet sodas to see if that benefits their weight-loss efforts. An analysis published in the “American Journal of Public Health” in 2014 pointed out that, given the evidence that diet soda leads to weight gain, people who continue drinking it will have to cut back on their solid food intake if they want to lose weight. However, eating fewer solid foods reduces your intake of beneficial nutrients like protein and fiber, which fill you up and thereby aid in weight loss.