While your taste buds might enjoy that diet soda, your ticker probably doesn't …
illustration of a hand holding a soda
Credit: Getty Images

The average American adult consumes 77 grams of sugar (a little more than 6 tablespoons) per day, according to the American Heart Association. Compare that to the AHA's recommended limits for added sugars …

  • Men: at most 36 grams, which equals 9 teaspoons or 150 calories, per day
  • Women: at most 25 grams, which equals 6 teaspoons or 100 calories, per day

For reference, a 12-ounce regular soda contains 32 grams (8 teaspoons) of added sugar. Many of us have been trying to avoid added sugars for years. Consuming too much sugar, and in particular sugar-sweetened beverages, has been implicated in weight gain, obesity, type 2 diabetes, high blood pressure and cardiovascular disease. Indeed, a 14½-year study published in 2014 in JAMA Internal Medicine found that people who consumed 17% to 21% of their calories from added sugar had a 38% higher risk of dying from heart disease (compared to those who consumed 8% or fewer of their calories from added sugar). So we turn to artificial sweeteners. Hey, if a diet soda has zero sugar, it's a better choice, right?

A new study published September 7 in the journal BMJ has some not-so-sweet news if that's been your solution to lowering your sugar consumption. People who consume higher amounts of artificial sweeteners potentially have a 9% higher risk for heart disease and an 18% higher risk for stroke compared to their peers who consume no artificial sweeteners.

Read on to find out more about the potential connection between sugar substitutes and cardiovascular disease, then discover other ways to lower your sugar consumption in heart-healthy ways.

What This Heart Health Study Found

To reach this conclusion, a group of French researchers analyzed data from more than 103,000 French adults who took part in an online nutrition study. At the beginning of the study, the participants (who had an average age of 42 at the start and were about 80% female), completed questionnaires about diet, health, exercise, education, smoking status and occupation. They also filled out several diet assessments at the launch and every six months after for an average of nine years. These included a 24-hour diet recall, in which each person was told to report every food and drink they consumed in the last day.

The scientists used these reports to estimate consumption of artificial sweeteners, fruits, veggies, dairy products, red meat and other categories of foods. Participants also shared any new health events, including biometric reports and diagnoses, including for heart disease, heart attack and stroke.

About 37% of these individuals reported consuming artificial sweeteners in some form, to the tune of approximately 42 milligrams per day on average. That's equal to a single packet of sweetener (like the kind you might add to a coffee or tea) or about 3½ ounces of diet soda. Among the highest consumers, the average was about 78 milligrams (about 6 ounces of diet soda). Some consumed none.

Diet soft drinks made up about 53% of the total artificial sweetener consumption, the researchers estimated. Other top-ranking sources were sweetener packets (30%) as well as artificially sweetened yogurts and cottage cheese (8%). Beyond the fully synthetic sweeteners, the scientists also asked about more-natural low- or zero-calorie sweeteners like plant-based allulose, monk fruit or stevia. The participants consumed too little of these to be significant enough to research.

Compared to non-consumers, those who ate or drank products with the most sugar substitutes differed in a few ways:

  • Were more likely to be younger
  • Had a higher body mass index (BMI)
  • Were more likely to smoke
  • Tended to be less physically active
  • Were more likely to be following a weight-loss diet of some kind
  • Consumed fewer calories, saturated and polyunsaturated fats, fiber, carbohydrates and fruits and vegetables
  • Consumed more sodium, red and processed meats and dairy products
  • Drank less alcohol

Taking into account these other differences and variances in age, sex, activity, education, smoking status and family history of heart disease, the scientists discovered that the subjects who fell under the "high consumer" umbrella for artificial sweeteners had a 9% higher risk for heart disease compared to those who consumed none. The highest consumers were also at 18% higher risk for stroke.

The researchers also tried to determine which was worse for heart health: added sugars or artificial sweeteners. They said that artificial sweeteners "should not be considered a healthy and safe alternative to sugar," but the jury is still out.

The Bottom Line

More research—including studies that include more accurate diet monitoring than self-reports (it's easy to fib or forget)—are needed to confirm these results. Future studies should also include a more diverse participant pool, and a more even gender breakdown.

Until we learn more, it's wise to stick with the World Health Organization recommendation of consuming 10% or less of daily calories from added sugars; ideally about 5% or less if you ask the AHA. Watch for these top 7 sources of added sugars. And try to limit your consumption of artificial sweeteners like aspartame, sucralose, acesulfame potassium and saccharin. More research is also needed about more natural low- or zero-calorie sweeteners and sugar alcohols like xylitol, erythritol, allulose, stevia and monk fruit, but the less sweetener you add the better.

Stick with natural sugars from fruit, when possible, and try our 30-Day Slash Your Sugar Challenge to help you step down slowly.