But perhaps the only seemingly good thing about diet soda—it's apparent weight-loss-friendly lack of calories—is seen as kind of a hoax now, thanks to new research from Johns Hopkins University that shows heavy people using diet soda as a weight-loss tool actually wind up eating more food. That kind of defeats the purpose of drinking diet soda in the first place.
This is the first study to look at national patterns of diet beverage drinking and calorie intake by body weight. We talked to lead study author Sara Bleich, PhD, associate professor with the Bloomberg School's department of health policy and management, to look further into the main points of her new research:
• Major takeaway #1: About 1 in 5 overweight or obese adults consume diet soda (about twice as many as healthy-weight adults).
• Major takeaway #2: Overweight and obese adults who drink diet beverages eat an amount of total calories comparable to what heavier adults who drink sugary drinks do, but they then go on to consume significantly more calories from solid food at both meals and snacks.
• Major takeaway #3: When adults replace sugary beverages with diet beverages, they do not appear to make other changes to their diet.
It appears there's something metabolic at play. "Available evidence suggests that artificial sweeteners, which are present in high doses in diet beverages, are associated with a greater activation of reward centers in the brain which alter the reward a person experiences from sweet tastes," Bleich explains. "Another way of thinking about this is that for diet-beverage drinkers, the brain's sweet sensors may no longer provide a reliable gauge of energy consumption."
As a result, drinking diet soda could result in cravings and eating more food because the artificial sweetener disrupts appetite control, she explains.
Diet soda's also a likely culprit in America's obesity epidemic, too. In 1965, just 3 percent of Americans indulged in the chemical-laden drinks. Today, it's 20 percent. Soda in general seems to accompany other unhealthy diet habits. People who drink both sugary and diet sodas also eat lots of salty and sweet snacks—about 20 percent of their total diet.
The study appeared recently in the American Journal of Public Health.
For more reasons to ditch your soda habit, read 9 Disturbing Side Effects of Soda.