At face value, diet soda seems like a sensible choice. A beverage that has zero calories, zero sugar and no carbohydrates has to be healthy, right? Well, not exactly. Before you guzzle down another can of diet soda, you might want to know that your zero-calorie fizzy drink carries some not-so-sweet health risks—from tooth erosion to bone loss to adding inches to your waistline.
Here are 6 compelling reasons to curb your diet soda addiction once and for all.
It may lead to weight gain.
If you think diet soda is the panacea of weight loss, think again. It sounds counterintuitive, but diet soda can actually lead to weight gain. One of the biggest reasons, says Susans E. Swithers, Ph.D., a professor of Behavioral Neuroscience at Purdue University, is purely psychological. When individuals choose diet soda over regular soda, they may get a false sense of virtuosity that may help them to justify indulging later on.
“There’s this sort of cognitive distortion that occurs,” explains Swithers, who conducted a 2013 review examining the negative impact of artificially sweetened beverages on weight and other health outcomes. “We have data to show that people do this kind of thinking—‘Well, I’m having a Diet Coke, so I can have another piece of pie.’”
A 2014 study from Johns Hopkins University backs up this theory. In the study, which was published in the American Journal of Public Health, researchers found that overweight Americans who drink diet soda compensate by consuming more calories from food. So if you’re making the switch from regular soda to diet, don’t fall victim to the “health halo” surrounding diet soda—just because it’s calorie-free doesn’t give you a free pass to eat a cookie.
It messes with your metabolism.
To mimic the sweet taste of regular soda without the calories, most diet sodas are sweetened with chemicals such as sucralose, aspartame, saccharinor acesulfame potassium. These artificial sweeteners might cause weight gain by interfering with the body’s metabolic responses that normally contribute to glucose and energy homeostasis, Swithers wrote in her study, which was published in Trends in Endocrinology & Metabolism.
In lab studies, rats and mice that ingested artificial sweeteners actually gained more weight over time compared with animals that received the same diets mixed with sucrose or glucose, largely because the sweeteners created what Swithers calls “metabolic dysfunction.”
“When we consume something that tastes sweet, our bodies have learned to anticipate energy and calories,” explains Swithers. “But when you drink a diet soda and your body doesn’t get the calories and sugar that it’s supposed to, your brain gets conflicting signals and the body no longer produces the same kind of responses.”
Artificial sweeteners, she says, can blunt our body’s learned responses to sugar, so that when we do consume, say, a piece of cake, our brain’s normal satiety cues don’t kick in, making us feel less full. What’s more, because artificial sweeteners are so intensely sweet, they can desensitize our taste buds and make subtly sweet foods (such as carrots) seem less sweet.
It may weaken your bones.
Drinking cola—diet or regular—may set you up for osteoporosis later on. In the The Framingham Osteoporosis Study, a a study that compared bone density in 2,538 men and women with their self-reported intake of soda, women who regularly drank colas had significantly lower bone mineral density at each hip site, a key indicator of osteoporosis risk. The reasons are unclear, but researchers speculate that cola might have been displacing milk and other bone-building beverages, or that bone loss was due to the phosphorous acid found in colas, which can deplete calcium stores.
It can damage your teeth.
According to a case study published in the March/April 2013 issue of General Dentistry, diet soda was purported to have the same effect on tooth enamel as methamphetamine or crack cocaine use. The study examined three representative cases—including a methamphetamine user, a crack cocaine addict and an avid consumer of diet soda—and found that all three individuals suffered severe erosion of the tooth enamel. The high acidity of diet soda can weaken tooth enamel, leaving the tooth more vulnerable to decay (read: more trips to the dentist).
“I’d see erosion once in a while 25 years ago, but I see much more prevalence nowadays,” said Kim McFarland, D.D.S., associate professor in the University of Nebraska Medical Center College of Dentistry in Lincoln, in a press release statement. “A lot of young people drink massive quantities of soda. It’s no surprise we’re seeing more sensitivity.”
It is associated with a higher risk of type 2 diabetes.
Although diet soda is touted as safe, sugar-free alternative for individuals with diabetes, a number of studies have discovered a paradoxical link between diet soda consumption and a greater incidence of type 2 diabetes. A 2009 multi-ethnic study published in Diabetes Care found that daily consumers of diet soda had a 67 percent elevated risk of type 2 diabetes compared with non-consumers. Following on the heels of that, a 2012 French study published in the American Journal of Clinical Nutrition also discovered a link between artificially sweetened beverages and type 2 diabetes. Although additional trials are needed to establish a causal link between type 2 diabetes and artificially sweetened beverages, these findings provide yet another reason to kick the can.
It may be bad for your heart.
A preliminary study has hinted at an association between daily diet soda consumption and a heightened risk of heart disease. Researchers at University of Miami and Columbia University followed roughly 2,500 New Yorkers for 10 years and found that daily diet soft drink consumption was associated with a 44 percent greater risk for vascular events such as stroke or heart attack. Further research needs to be done to determine whether diet soda causes heart attacks, or whether the individuals who consume diet soda have poorer overall dietary patterns that lead to vascular events. Still, the findings, which were published in the September 2012 General of Internal Medicine, present another potential strike against diet soda.
Bottom line? The occasional diet soda is unlikely to yield serious harm. But it’s hard to ignore the growing body of evidence that points to the negative health outcomes associated with daily diet soda intake. Luckily, healthier options for low-calorie beverages abound—from unsweetened tea to coffee to plain-old water.
“We want to encourage people to be mindful of their soft drink consumption,” Swithers says. “In many ways, we have seen this cultural shift where 30 years ago, people didn’t drink sweetened beverages every day—they were a treat. When you start to consume soft drinks every single day, that’s when it can become problematic.”