Ever eat a burger and fries, and wash it down with a diet soda? You're not alone, and you're probably not "saving" as many calories as you think by consuming diet beverages.
A new study examining the dietary habits of more than 22,000 U.S. adults found that people who drink diet beverages may compensate for their low-calorie drink choices by eating foods loaded with sugar, sodium, fat and cholesterol. The findings were published Friday in the Journal of the Academy of Nutrition and Dietetics.
Ruopeng An, a kinesiology and community health professor at the University of Illinois, analyzed 10 years of data from the National Health and Nutrition Examination Survey, conducted by the National Center for Health Statistics, which asked participants to recall everything they ate or drank over the course of two nonconsecutive days.
When considering calorie intake, An looked at five types of drinks: sugar-sweetened beverages, such as sodas and fruit drinks; diet or sugar-free drinks, coffee, tea and alcohol. He also compiled a list of "discretionary foods" -- high-calorie, nutrient-poor foods that do not provide essential nutrients that the human body needs but may add variety. Foods such as cookies, ice cream, french fries and pastries fall under this category.
More than 90 percent of people surveyed ate discretionary foods daily -- averaging about 482 calories from these products per day -- and about 97 percent consumed at least one of the five types of drinks every day. Many drank two or three different types of beverages daily.
An's analysis showed that drinking alcohol was associated with the largest increase in daily calorie intake at 384 calories. This was followed by sugar-sweetened beverages (226 calories), then coffee (108 calories), diet beverages (69 calories) and tea (64 calories).
But while people who drank coffee and diet beverages consumed fewer total calories per day, they obtained a greater percentage of their daily calorie intake from the unhealthy discretionary foods, suggesting a compensation effect, An said.
"It may be that people who consume diet beverages feel justified in eating more, so they reach for a muffin or a bag of chips," he said in a statement. "Or perhaps, in order to feel satisfied, they feel compelled to eat more of these high-calorie foods."
Another possible explanation An offered was that people might feel guilty about indulging in unhealthy foods, and then compensate by drinking diet beverages.
"It may be one or a mix of these mechanisms, but we don't know which way the compensation effect goes."
Further analysis showed that the incremental daily calorie intake from unhealthy foods associated with diet beverage consumption was highest in obese adults.
Additionally, African Americans who drank diet beverages, sugary drinks and coffee, as well as Hispanics who consumed alcohol, had the highest daily calorie intakes across all of the racial and ethnic groups.
An concluded that diet drinks may not help people control their weight if they're not paying attention to the types of food they consume.
"If people simply substitute diet beverages for sugar-sweetened beverages, it may not have the intended effect because they may just eat those calories rather than drink them," he said. "We therefore recommend that people carefully document their caloric intake from both beverages and discretionary foods because both of these add calories -- and possibly weight -- to the body."