科学美国人60秒:Color-Coded Food Helps Consumers Make Healthful Choices

You might not know how many calories were in that sandwich. But if you got lunch at the Massachusetts General Hospital cafeteria, you could tell with one glance whether you'd made a healthful choice: offerings are color-coded.

Simply posting calories does not always get consumers to make healthier choices. So researchers tried something different.

Mass General’s cafeteria food and beverage options were classified as least, somewhat or most healthful with red, yellow or green labels. Green is healthiest. Researchers then tracked some 4,600 employees.

About six months after the changes were made, the purchases of "red" label food decreased by more than 15 percent, and "red" beverages dropped by 39 percent. "Green" food and drink purchases increased, according to the study in the American Journal of Preventive Medicine. [Douglas Levy et al., Food Choices of Minority and Low-Income Employees]

Making healthy food choices easier could especially help the poor the undereducated, the very populations most affected by the obesity epidemic. Mass General employees from those groups made the biggest improvements.

—Katherine Harmon