A city health department regulation requires food chains like Subway, Starbucks and McDonald’s to display the calorie counts on their menus.

This regulation was enforced keeping in mind the effect it would have on consumers who would at least pause and have a look at the calorific content of the donut before buying it every morning. The law was indeed resisted by food companies.

The researchers were unsure whether this law would lead to a decrease in calories consumption or to a paradoxical effect called “portion distortion”. This has now been made mandatory by both House and Senate health care drafts to require most restaurants to list calorie counts on their menu.

The city’s health department kept a record of the calorie consumption at 13 different chains and four chains showed significant decrease in the total amount of calories consumed: McDonald's, Au Bon Pain, Starbucks and KFC.

The above four food chains saw decrease but Subway saw an increase in the consumption of calories.

The study had a self-reporting element, and consumers who knew about the labeling reported consuming a little over 100 calories than those who did not know about it.

Whether the menu labeling has helped people live more healthily or not is not certain. It may have helped people who were already living together. People with access to information about obesity can easily use menu labeling to their advantage.

On the whole increasing awareness of calorie contents didn’t decrease the total number of calories consumed, and it did not have any specific effect in areas where the obesity problem is especially acute.

Robert Wood Johnson Foundation funded the study.