- Although diet sodas are often marketed as a weight loss tool, growing evidence suggests diet drinks and the artificial sweeteners they contain may actually promote weight gain, according to a recent Harvard study published in PLOS.
- After tracking low-calorie sweetener consumers for 10 years, Harvard researcher Vasanti Malik found that the low-calorie sweetener users were heavier and had larger waist circumferences and more abdominal obesity than non-users.
- A past study found that drinking diet soda was associated with an almost doubled risk of becoming overweight or obese, but a shorter-term 2012 study found that people who replaced sugary soft drinks with diet beverages lost weight after six months.
There have been conflicting studies about the impact of diet sodas for almost as long as the beverages have existed. With no clear answer, scientists continue to question whether artificial sweeteners are a benign substitute. Many consumers, however, are beginning to listen to some of the less promising reports.
In the past decade alone, American consumption of diet soda has fallen by more than 27% — a loss of 834 million cases. The category went from accounting for nearly 30% of all carbonated beverages by volume sold in the U.S. to approximately 25%, according to Beverage Digest data.
Brooke Alpert, author of “The Sugar Detox,” said in her book diet sodas have more intense flavor than real sugar, so over time products like diet soda dull our senses to naturally sweet foods like fruit. Even more troubling, she wrote, these sugar stand-ins have been shown to have the same effect on your body as sugar—they trigger insulin, which sends your body into fat storage mode and leads to weight gain.
Most nutritionists agree that aspartame, one of the most common artificial sweeteners, is safe to consume. Last year, PepsiCo announced that it was cutting aspartame from Diet Pepsi due to consumer demands. It replaced sugar with sucralose, known by the brand name Splenda.
Some newer diet sodas to the market — like Zevia — have experimented with stevia, an herbal extract that some claim is safer and provides better taste than Splenda. Coca-Cola has even experimented with stevia in some of its brands, such as Coca-Cola Life and Sprite. However, many consumers have yet to buy into the craze.