People often underestimate how much—and how many calories—they eat. Sometimes it’s wishful thinking, self-deception or lack of knowledge about serving sizes and calorie counts. Context matters, too. A series of studies published in the Journal of Consumer Research shows that the order in which we contemplate food can distort how we estimate calories.
In one study, for instance, people were asked to estimate how many calories a cheeseburger had—the average guess was 570 calories. But when they were first asked to estimate the calories in a salad, and then in the cheeseburger, they guessed the burger had 787 calories—38 percent more. In another study, when people considered cheesecake first, they saw the cheeseburger as relatively low in calories. But after contemplating fruit salad, the burger looked 33 percent more caloric than before.
Bottom line: If you’re trying to control your weight, start your meals with a low-calorie salad. Not only will it help fill you up, but it may make you choose a lower-calorie main course. And don’t trust your guesstimates—read the calorie counts.