Lets say you go to McDonald's. You see that they have a salad on the menu. Would you get the salad, or something less healthful, like a cheeseburger and French fries?
Fries... The Popular Choice
Some people may say the salad. But a recent study suggests otherwise. Researchers showed people two fast food-type menus: one with three typically unhealthful items, like a hamburger, a chicken sandwich and French fries; and the other menu had the same items but also included a salad.
The people who saw the menu with the salad were nearly three times more likely to choose the least healthful item, the French fries. Almost nobody actually chose the salad.
Seeing Is Fulfilling
It may sound absurd, but the presence of the salad as a healthy choice somehow spurred people to make the most unhealthy choice. It's called vicarious goal fulfillment.
The idea is that merely seeing and considering the salad fulfills your goal of eating healthfully. Then you feel like you've done your duty, and go on to order what amounts to an unhealthful treat, like extra large fry or a huge hamburger.
It's possible that simply knowing about this phenomenon could help in your eating decisions. If you know the salad could encourage you to get a cheeseburger, perhaps it's possible to realize what's happening and resist the urge.
For more information on vicarious goal fulfillment and eating healthy, check out this article from WebMD.