As part of a comprehensive effort to stem the rise in obesity, King County, Wash., enforced a mandatory menu-labeling regulation requiring all restaurant chains with 15 or more locations to disclose calorie information at the point of purchase beginning in January 2009.
The goal of the study was to examine the effect of this menu labeling on calories purchased, and secondarily, to assess self-reported awareness and use of labels.
Fifty sites from 10 chain restaurants in King County were selected through stratified, two-stage cluster random sampling. A total of 7,325 customers participated. In order to qualify to participate, the customers had to be at least 14 years old, be an English speaker, and have an itemized receipt. The study population was 59% male, 76% white non-Hispanic, and the majority was less than 40 years old. The participants were followed 18 months after implementation of the law.
The researchers found that after the regulations were put in place, more people reported being aware of posted calorie information. After 18 months, customers of taco restaurants consumed fewer overall calories and customers of coffee establishments consumed fewer calories from beverages. Those results may be due to "customization,"—people can decide whether to put additional calories of sour cream or guacamole on a taco, for example. In coffee houses, customers choose the size and the additives for a drink.
There was not much change seen among burger and sandwich restaurant patrons. In addition, women purchased fewer calories than men as a result of menu labeling, particularly at coffee establishments.
The researchers concluded that: "Mean calories per purchase decreased 18 months after implementation of menu labeling in some restaurant chains and among women but not men." διατροφικές πληροφορίες που παρέχονται στα μενού των εστιατορίων συμβάλλουν στο περιορισμό της ενεργειακής πρόσληψης των γυναικών