Washington: A sixth of fast food addicts cut down on junk food with higher calories after the US introduced a calorie-labeling system in 2008. (Agencies)
Researchers from the New York School of Public Health and other centers found there has been a small but positive impact.
Analysis showed that 15 percent of customers using calorie information purchased food items with significantly lower calories than customers who did not see or use the calorie information.
Obesity rates in the US are at an all time high in both adults and children and currently a third of adults and 17 percent of children and teenagers are obese.
Several studies support an association between fast food consumption and excessive energy intake, but customers often underestimate the number of calories in restaurant meals, the journal reports.
Surveys were carried out during lunchtime hours in spring 2007 (one year before the regulation) and in spring 2009 (nine months after its implementation) at 168 randomly selected locations of the top 11 fast food chains in the city, according to a New York School statement.
Adult customers provided register receipts and answered survey questions. Data from 7,309 customers in 2007 and 8,489 customers in 2009 were analysed. Overall, there was no decline in calories purchased across the full sample. However, three major chains saw significant reductions.
For example, at McDonalds, average energy per purchase fell by 5.3 percent, at Au Bon Pain, it fell by 14.4 percent and at KFC, it dropped by 6.4 percent. Together, these three chains represented 42 percent of all customers in the study.
High street chains in England are about to embark on a similar, though voluntary scheme, as part of the government's Public Health Responsibility Deal.
Susan Jebb from the MRC Human Nutrition Research Centre in Cambridge, Britain believes that labelling is a step forward, but changes in food supply must follow.
She writes, "Calorie labeling will help consumers make an informed choice about what they eat, but sustained improvements in the nation's diet will require a transformation of the food supply too."
Washington: A sixth of fast food addicts cut down on junk food with higher calories after the US introduced a calorie-labeling system in 2008.