One of the laws of dieting we've long subscribed to is the canceling-out theory: If you eat a salad with a piece of cheesecake, they cancel each other out calorie-wise. Right?
We're joking, of course, but a new study finds that some people might actually think there's something to that, even if they're not completely aware of it. Researchers presented 934 participants with various food pairings and asked them to estimate calories. "Vice" foods (cheeseburgers, cheesecake) were sometimes paired with similar "bad" foods, sometimes with "virtue" foods such as salads, and sometimes with foods that were a mixture of virtue and vice, such as low-fat cheesecake.
In one scenario, the study subjects were shown a bowl of chili with cheese, and a bowl of chili with cheese along with a small green salad. Those who saw only the chili estimated the calories at an average of 699, while the chili with the salad was estimated at 656 calories.
"Because people believe that adding a healthy option can lower a meal's calorie content, the negative calorie illusion can lead to overconsumption, thus contributing to the obesity trend," said study author Alexander Chernev in a news release. Chernev is an associate professor of marketing at the Kellogg School of Management at Northwestern University.