Growing, Olivia Dreizen Howell, 39, ‘lived on’ diet soda. So did her family. At a family reunion in 1996, everyone wore T-shirts with their shared last name in Diet Coke-can font. “We drank Diet Coke, Diet Ginger Ale and Diet Sprite like water – there was no difference in our household,” she says.
Like many, Howell believed that sugar-free soda was a benign choice. But the latest research is calling this assumption into question, as diet drinks have been linked to mood disorders, the development of fatty liver disease, autoimmune diseases and cancer, to name a few.
Before you throw your diet soda down the drain (a step that one health expert actually recommends), know this about diet soda research: The vast majority of it is observational — drawn from public health records and long-term populations. studies – as opposed to the scientific gold standard of double-blind, placebo-controlled studies.
Here’s what we know so far about what diet soda can do to your health.
Diet soda is linked to a higher diabetes risk
“Type 2 diabetes appears to be the strongest link” when it comes to diet soda and health risks, says Susan E. Swithers, a professor of neuroscience at Purdue University who studies the effects of diet soda on metabolic health. consistent finding.” A 2023 study of nearly 106,000 people found that people who consumed more artificial sweeteners had a higher risk of type 2 diabetes than people who did not eat or drink anything.
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Previous work by Swithers has shown that people who drink a lot of diet soda are at increased risk for excessive weight gain, type 2 diabetes, cardiovascular disease and metabolic syndrome, a constellation of conditions including excess body fat (especially in the middle), elevated blood sugar and blood pressure, and higher triglycerides – “these are all risks for the development of type 2 diabetes and heart disease,” says Dr. Barry Schuval, an endocrinologist at Northwell Health.
It is linked to poorer heart health
Several studies have linked artificially sweetened drinks such as diet soda to heart problems, particularly an increased risk of stroke, coronary artery disease and heart attacks. Most recently, a March 2024 study found that people who drank more than two liters of artificially sweetened drinks per week had a 20% higher risk of atrial fibrillation than people who did not consume sweetened drinks. “It’s important not to assume it’s low-calorie [diet drinks] are naturally healthy,” said Dr. Ningjian Wang, lead author and professor of endocrinology and metabolism at Shanghai Ninth People’s Hospital in China.
Melissa Perst, a dietitian and spokesperson for the Academy of Nutrition and Dietetics (who was not involved in the study), emphasized that the observational nature of the study means we don’t know why this association occurred. Before we can draw conclusions about whether diet drinks increase the risk of atrial fibrillation, we need more research “to understand all the potential variables, such as health conditions, body weight, physical activity and other dietary habits,” says Prest.
Diet soda is linked to cancer
In July 2023, after reviewing research on humans and animals, the World Health Organization (WHO) added aspartame, a common ingredient in diet soda, to a list of ingredients that are “possibly carcinogenic to humans.” That may sound worse in theory than in practice: The WHO concluded that a person weighing about 150 pounds can safely drink about eight cans of aspartame-sweetened diet soda per day.
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Even with this designation, aspartame is not necessarily carcinogenic, Schuval says. “We must remember that correlation does not necessarily imply causation,” he says, and the existing research is inconclusive.
Other research has shown a possible link between diet soda and cancers, including colon, uterine, kidney and pancreatic cancer. But instead of diet soda being the culprit, weight gain could be, Schuval says.
Diet soda is linked to weight gain
Artificial sweeteners such as aspartame, sucralose and saccharin are much sweeter than sugar and can alter the sweet taste receptors in your body. Some experts think this may cause changes in your body’s hunger and satiety hormones, causing you to eat and drink more than you otherwise would. However, the theory is not a slam dunk. “Although this change has been frequently reported in animal studies, human studies have produced inconsistent results,” says Prest.
Another possibility is that both sugars and artificial sweeteners can disrupt the healthy balance of gut bacteria in the gastrointestinal tract, leading to the development of insulin resistance and type 2 diabetes, says Prest. This, too, is difficult to prove in studies, and studies pointing to this path are often small and inconclusive, says Leah Reitmayer, a dietitian in Sanford, NC.
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As is the case with much nutritional research, the associations found between diet soda and weight gain (and obesity) may be a red herring. “The research shows that more obese people drink diet soda than regular ones, but also eat more food than healthy-weight adults,” says Reitmayer. More research is needed to determine whether diet soda makes people gain weight, or whether the relationship is complicated by other factors.
What do you think of all this research?
Overall, the findings are mixed, leading to consternation among consumers as to whether diet soda is a safe drink.
Swithers believes we still have more questions than answers. Although she says she feels convinced by a real link between diet soda and type 2 diabetes, the evidence that artificial sweeteners contribute to cancer and heart disease is less clear, she says. “It just comes down to what explains that relationship,” Swithers says. Are people who choose to drink diet soda already at greater risk for certain health problems? Are all artificial sweeteners the same? Is there another variable that scientists don’t look at?
“That’s where it gets really muddy,” she says. Unfortunately, we’ll have to wait to get a more complete picture of the health effects of diet soda.
Is diet soda better for you than regular soda?
If you routinely drink sugary soft drinks, all experts would prefer you switch to water (of course). But other than that, many would prefer you to drink diet. “Some people find that artificially sweetened drinks help them better control their blood sugar levels,” says Prest.
Another reason is that we have much more compelling evidence for the harms of excess sugar than for artificial sweeteners. For many years, research has linked sugar to conditions such as obesity, inflammation, heart disease, metabolic syndrome, insulin resistance, type 2 diabetes or worsening prediabetes, weight gain and tooth decay. America’s food supply could save money and lives.
It’s also important to consider what else could replace your diet soda. Dan DeBaun, a 32-year-old public relations executive in Minnetonka, Minnesota, uses diet soda as a means to cut back on alcohol. “I never drank a lot of alcohol before, but I wanted to cut back even more after more research came out about its negative health effects,” he says. After a successful ‘dry October’ in which he completely abstained from alcohol, he realized that he still liked to have a drink when he was out with friends or at a sporting event or concert. So he ordered a Diet Coke or a Diet Pepsi.
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“Diet soda doesn’t necessarily make me feel great while I’m drinking it, but I consider it a net positive compared to alcoholic beverages,” says DeBaun. “I only drank one, but I found it was a good substitute.”
And dentally speaking, diet soda clearly outperforms regular ones. “One benefit of artificial sugars is their role in reducing dental caries,” says Prest. “When sugar-sweetened drinks are swapped for artificially sweetened drinks, the risk of developing dental caries or cavities is reduced,” she says, and this is due to the reduction in the growth of the bacteria that cause them.
How to limit or stop your diet soda intake altogether
Few of us can quit the hard diet-soda habit cold turkey, but there’s still plenty you can do to cut back, says Swithers.
Throw it down the drain (really)
People usually think they need to eat or drink more to feel satisfied than they actually do. If you’re just craving the taste of diet soda, open a can or bottle, take a few sips, and throw the rest down the sink. Your craving may be satisfied after just a few sips. “Drinking a little bit, then stopping and thinking about whether you want more soda can be a helpful step in reducing consumption,” says Swithers.
Treat your diet soda like candy
Instead of thinking of your diet soda as a drink, think of it as candy, Swithers suggests. That way, it can seem ridiculous to have one with a meal. “Most adults wouldn’t open a bag of candy and pour it on their plate,” she says. “Just because it’s in a glass doesn’t make it magical. Would you serve a bag of jelly beans as a side dish with your meal?
Hide your water
Many people drink diet soda because they don’t like the taste of water. To give a glass of water an attractive taste, you can put some frozen fruit in it (especially the kind that has juice, such as pineapple, strawberries and mango). If you use seltzer instead of still water, it will feel even more like the fizzy treat you love.