The trend toward super-sizing fast-food portions has raised concerns among health experts worried about U.S. obesity rates. But a new study has found the opposite approach – offering fast-food customers “downsized” portions – is an effective way to deter overeating.

Tulane University researchers, reporting in this month’s Health Affairs journal, said when restaurant servers asked customers if they’d like to “downsize” starchy side dishes at a Chinese fast-food restaurant up to one third gladly cut back.

The average savings: a whopping 200 calories each meal.

“Our goal was to test whether the invitation to downsize a meal component would be embraced by consumers and, importantly, whether the approach would be more effective than a purely information-based approach – in this case calorie labeling,” said lead study author Janet Schwartz, assistant professor of marketing at Tulane’s A.B. Freeman School of Business, in a university release on the study’s findings.
Schwartz and her colleagues conducted several field experiments at a single Chinese fast-food restaurant. In each case, servers asked customers selecting side dishes, “Would you like to save 200 calories or more by taking a smaller portion?”
Sometimes, customers were offered a 25-cent discount if they took the downsizing offer. Other times, menu calorie labels were prominently displayed in front of consumers as they selected their meals.
In all, 14 percent to 33 percent of customers opted to downsize portions. Surprisingly, the 25-cent discount had little impact on downsizing choices and the calorie postings didn’t persuade much either.

Schwartz hopes the study helps restaurants understand that helping diners exercise portion control won’t alienate customers.
“I think the restaurant industry may find this counterintuitive, but it’s an interesting and easy strategy to implement that could help their customers make healthier choices,” Schwartz said.