NEW ORLEANS – Downsizing portions is more effective than calorie warnings at convincing diners to eat less, according to a new study released by Tulane Univ.

Roughly one-third of diners downsized starchy side dishes at a Chinese fast-food restaurant when given the option. This saved an average of 200 calories each meal. Lead study author Janet Schwartz, assistant professor of marketing at Tulane, said the goal of the study was to test whether consumers would embrace the option to downsize a meal component and whether the downsizing approach would be more effective than calorie labeling.

Schwartz and other researchers conducted several field tests at a single Chinese fast-food restaurant. Servers asked customers “Would you like to save 200 calories or more by taking a smaller portion?”

Customers were offered a 25-cent discount if they took the downsizing offer in one scenario. In another, calorie labels were prominently displayed as diners selected their meals and in another calorie labels were removed. The study revealed that roughly 14 percent to 33 percent of customers opted to downsize portions. However, the 25-cent discount had little impact on downsizing choices, according to the study. The calorie postings also had little impact as more customers — 21 percent versus 14 percent — accepted the downsizing offer when calorie information was absent.