Is Diet Soda Destroying Your Health?

November 1, 2018

A nutritionist gives the final word on whether you should be sipping zero-calorie carbonated beverages.

closeup of soda cans

Diet soda has had a particularly bumpy PR ride. Heralded for decades as a weight-loss elixir, it eventually became the focus of cancer concerns before being labeled a possible co-conspirator in the obesity epidemic.

It’s almost enough to make you swear off diet soda for good. Except for, you know, the fact that it’s a no-calorie way to satisfy your sweet tooth. And it tastes pretty darn good.

All in all, it’s a tempting solution—tempting enough that the National Center for Health Statistics says that one in five people, both kids and adults, consume a daily diet beverage.

But are they really safe to drink? Can they make you gain weight? We turned to Nathan Myers, M.S., R.D., C.D.N., a clinical dietitian at James J. Peters VA Medical Center in New York City, to render a verdict on the health impact of diet sodas.

The Skinny Behind Diet Sodas

The first no-calorie carbonated drink was introduced in 1952—a sugar-free ginger ale called No-Cal that was first marketed to people with diabetes and later to weight-conscious women.

By the early 1960s, Coca-Cola and Pepsi had both introduced diet products: Tab and Patio Diet Cola (the name was changed to Diet Pepsi in 1964), respectively. Diet Coke didn’t hit the market until 1982.

Early diet sodas used two common artificial sweeteners: cyclamates and saccharin. But cyclamates were banned in 1970 based on evidence that a mixture of cyclamates and saccharin cause cancer in lab rats. Saccharin alone was also suspected of being a carcinogen, and the FDA proposed a ban in 1977. Consumer backlash caused Congress to pass a moratorium preventing the ban, but a warning label was placed on any product containing saccharin until 2000. During this period, aspartame became the sweetener of choice and helped no-calorie carbonated drinks skyrocket in popularity.

As enthusiasm for diet soda grew, however, so too did concerns about aspartame, because it too was linked to an increased cancer risk. But Myers says that’s false.

“Years of research have not yielded a connection between diet soda and cancer,” Myers explains. “More recently, the research focus on artificial sweeteners shifted to obesity, as major studies showed an association between diet beverage consumption and higher BMI. This opposed the accepted advice that consuming low-calorie beverages supported weight loss.”

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But if no actual calories in diet soda are contributing to weight gain, what is?

Myers explains that researchers over the years have tried to answer this question with two major theories. The first, called “compensatory calories,” is when someone uses having a zero-calorie soda to justify other poor eating and drinking decisions. An example: “I’m having a diet soda, so it’s okay to eat these cookies.

The second potential culprit: addiction. Artificial sweeteners are much sweeter than sugar. Aspartame, for instance, is roughly 200 times sweeter than the natural stuff. The theory is that artificial sweeteners overstimulate taste receptors and make more nutritious foods, like fruits and vegetables, less palatable.

“This second wave of research hasn’t reached the level of true consensus,” Myers says, but it has health professionals and consumers alike taking a hard look at artificial sweeteners.

The Final Answer: Sip Carefully

While the research behind diet soda is still ongoing, Myers says that your safest bet is to reduce consumption of both sugar and artificial sweeteners.

“Recent research tells us that reduced consumption of foods and beverages with added sweeteners—artificial or otherwise—can potentially benefit everyone,” he says, “especially folks over 50, who face the challenges of slower metabolism and increased risk of health issues like high blood sugar in the years ahead.”

And, Myers points out, cutting down on sweeteners might rekindle a love of healthier foods. “Reducing sweetener consumption may improve the nutritional quality of your diet, as you cease drowning out the subtler flavors of nutritious foods,” he explains.

While your best beverage option is water, Myers has plenty of flavorful recommendations for those who want some variety.

“Naturally flavored carbonated water, or seltzer, is a popular option that can be free of both calories and sweeteners,” he says. Myers also recommends fruit-infused waters—both commercially available and homemade—because they provide similar hydration benefits, minus the carbonation.

“Diluted coconut water, unsweetened almond milk, and low-sodium vegetable juices also bring flavor to hydration with less than half the calories of traditional juices and sodas,” Myers adds.

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