Diet beverages rose in popularity primarily because they contain little to no calories. However, the calories that aren’t being consumed in these kinds of beverages are being consumed elsewhere. According to Dr. Ruopeng An, a University of Illinois Kinesiology and Community Health Professor, those calories are being consumed in the form of unhealthy foods.

Dr. An measured the caloric intake of over 22,000 individuals including their amount of consumption of five types of beverages: diet or sugar-free drinks, sugar-sweetened beverages, coffee, tea, and alcohol. An also cross-referenced people’s diets with a database created from the U.S. Department or Agriculture which included 661 foods categorized as “discretionary” — foods that aren’t important to one’s diet, such as cookies, ice cream and pastries. In other words, foods that should be avoided as part of a healthy diet.

What An found is that almost everyone from the study consumed one of the five types of beverages. Forty-three percent drank at least two. Even though coffee and diet-beverage drinkers consumed the least amount of daily calories, they also had the highest percentage of calories that came from the list of discretionary foods. What does that mean? It means that even though some of the study’s subjects had consumed less calories than some of the other study’s participants, those calories were more likely to cause someone to gain weight. Think of it like this: One person is eating donuts or cookies and another person is eating the same amount of calories (or even more) in vegetables and lean protein. Who’s more likely to gain weight quicker? Most likely the person eating the donuts and cookies.

There are times that you will see someone consuming a fast food meal that includes a double cheeseburger, medium French fries and a diet soda. That speaks directly to what the study states. It’s an illusion. Diet beverages do not allow you to eat more. Remember, it will always be a matter of what you eat or drink just as much as how much you consume.