Are “zero sugar” sodas healthier?
Traditional soda brands touting "zero sugar" are everywhere, but depending on the sweetener, they may not be much better for you.
Drinking sugar-laden regular soda is associated with an increased risk for metabolic syndrome, heart disease, and a list of other health problems. At the same time, diet sodas containing artificial sweeteners may not be much better, as some evidence suggests their frequent consumption may be linked with Type 2 diabetes and weight gain. So, how do the new wave zero sugar varieties of popular brands like Coca-Cola, Pepsi, and Dr Pepper measure up? Most contain a different formula of artificial sweeteners than diet sodas—and come with their own set of health concerns.
The problem with regular sodas
A 12-ounce can of cola packs 39 grams—nearly 10 teaspoons—of sugar. That’s more than the American Heart Association’s already generous recommended daily limit of 25 grams of added sugars for women and 36 grams for men. In the short term, this sudden rush can cause your blood sugar to spike and crash, which can leave you feeling tired and grumpy.
Over time, regularly drinking soda can have more serious effects. Repeated blood sugar surges can cause cells to become less responsive to insulin, a condition called insulin resistance. Both insulin resistance and a high-sugar diet can lead to high blood pressure, Type 2 diabetes, heart disease, and nonalcoholic fatty liver disease (NAFLD). Much of regular soda’s sweetness comes from highly processed high fructose corn syrup, which further contributes to the development of insulin resistance and NAFLD. And even if you exercise regularly, soda’s empty calories can promote weight gain, compounding these risks.
If this doesn’t turn you away, consider the hard numbers: One study suggests that sipping only one serving of a sugary drink—such as a soda—every day raises the risk of heart disease and Type 2 diabetes by 18 percent.
What are zero-sugar sodas?
According to the FDA, diet, sugar-free, and zero sugar products must have less than 0.5 grams of sugar per serving. Beyond that, there’s no specific regulation for diet and zero sugar labels; often, the difference is branding. The major soft drink manufacturers say it comes down to taste. According to Coca-Cola, Diet Coke has a blend of flavors for a lighter taste, while Coca-Cola Zero Sugar tastes more like the original. The same is true for other zero sugar varieties like Sprite and Dr Pepper.
Another distinction is the sweeteners. Typically diet drinks, such as Diet Coke, exclusively use the artificial sweetener aspartame. While most zero sugar drinks are mainly sweetened with aspartame, they also contain acesulfame potassium (another artificial sweetener) and sometimes a small amount of stevia (a natural sweetener). Although it’s less common, certain zero sugar drinks, such as Zevia, only use stevia, while others have a blend of stevia and the artificial sweetener erythritol (a sugar alcohol).
Are zero sugar sodas healthy?
Unlike the sugar in regular sodas, aspartame and acesulfame potassium in zero sugar sodas don’t raise blood glucose in the majority of people. They’re also calorie-free and generally recognized as safe by the FDA. But that doesn’t mean they’re good for you. They may impact your metabolic health in the following ways.
Hunger
The science on artificial sweeteners’ effect on appetite is mixed. Some research suggests that the sweet taste may confuse the brain because it receives sweet signals but no calories, in turn causing you to seek out something to eat. But this impact may depend on what blend of sweeteners is consumed. One study found that drinking a beverage with acesulfame potassium before a meal didn’t cause people to eat more, suggesting that its sweetness didn’t rev up appetite. And according to a meta-analysis of 11 clinical trials, stevia also doesn’t affect hunger levels, although more research is needed. Research on aspartame’s effects vary; some studies show it has no effect on hunger, while others suggest that it may increase appetite.
Gut health
Some experts think that regular consumption of zero sugar drinks and their artificial sweeteners may harm the gut in various ways. One theory is that, over the long term, aspartame suppresses the activity of an enzyme called intestinal alkaline phosphatase (IAP). When this happens, the gut becomes more permeable, leading to increased inflammation. It may also increase enzyme activity that leads to fat accumulation. Research done on mice suggests the same is true for acesulfame potassium: It alters enzyme activity, leading to increased inflammation and gut permeability, and possibly weight gain.
The science is murkier when it comes to the gut microbiome. Some human studies have shown that artificial sweeteners, including aspartame, reduce the diversity of bacteria in the gut. At the same time, other research suggests that artificial sweeteners don’t have much of an effect on the gut microbiome. Experts explain that these results are influenced by the number of people in the study and their lifestyles. Overall, more investigation is needed to make the call on how these sweeteners affect the gut.
Metabolism and brain function
Preliminary science suggests that the artificial sweeteners in zero sugar sodas may impact metabolism and brain function, but the real-world effects are still unknown.
In a mouse study, long-term consumption of acesulfame potassium increased insulin and leptin levels and altered activity in the area of the brain called the hippocampus, leading to impaired learning ability. Another study linked aspartame to memory and spatial learning problems and anxiety-like behavior in mice.
Experts suspect that these changes may be tied to how artificial sweeteners affect metabolism, but the science is conflicting. Some research suggests that high doses of aspartame cause oxidative stress, which may damage proteins involved in the insulin response. Scientists are also studying how changes in the gut microbiome may lead to metabolic syndrome. The strongest research is with saccharin and sucralose, two artificial sweeteners no longer as commonly found in zero sugar sodas.
Additionally, both aspartame and acesulfame potassium have been shown to raise the risk of developing Type 2 diabetes, although a direct link isn’t proven. Scientists note that people at risk for Type 2 diabetes may be more likely to drink artificially sweetened drinks, which could influence the study results. And other short-term studies show that aspartame and acesulfame potassium have no impact on glucose metabolism and diabetes risk. Overall, more research is needed to conclusively understand zero sugar soda’s impact on metabolism and brain health.
Heart health
Consuming artificial sweeteners is linked with an increased risk of cardiovascular disease, according to an observational study of more than 130,000 people. The researchers hypothesize that the sweeteners may inhibit bacteria in the gut microbiome that affect insulin sensitivity and produce enzymes that break down carbohydrates. In turn, this may increase the likelihood of high blood sugar and Type 2 diabetes—two risk factors for heart disease.
One preliminary study offers another potential mechanism: In mice, acesulfame potassium appears to interfere with fat metabolism in the liver. This accelerates plaque buildup in the arteries (called atherosclerosis) and leads to higher levels of LDL cholesterol and triglycerides.
So … are zero sugar sodas better for you?
Diet and zero sugar sodas are both made with artificial sweeteners that appear to come with health risks. Although more human and long-term study on the two main sweeteners—aspartame and acesulfame potassium—is needed, early research suggests that both may negatively impact gut and metabolic health. One thing that seems clear: these sweeteners and sodas aren’t good for you—that is, they don’t deliver anything your body needs, like nutrients.
So, given the choice between a regular soda and the zero sugar variety, go for the latter. But don’t make a habit of it. A better bet: Stick with good old-fashioned water, and when you need a change of flavor, reach for one of these soda alternatives that won’t spike blood sugar.
See how zero sugar sodas affect you
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