Most consumers worry about pollution and waste from fast-food containers, according to a new survey from Adweek and Harris Poll. In the survey of more than 1,000 U.S. adults, more than half said they’d be willing to consider reusable or returnable containers to address packaging waste at fast-food restaurants.

Young respondents, in particular, are paying attention to a company’s sustainability practices, said Kathryn Lundstrom, who covered the survey findings for Adweek. “Their opinions of brands are more likely to change as a result of seeing a brand change their behaviors to be more eco-friendly,” Lundstrom said.

But it’s one thing to say something on an online survey and another to alter consumption habits, especially when part of the appeal of fast food is convenience.

“It’s not clear that just because people want single-use plastics to go away, that they’re actually willing to change their behavior in order to support the models to make it happen,” said Shelie Miller, who teaches environmental sustainability at the University of Michigan.

And, Moller pointed out, switching to new packaging costs money; fast-food companies will likely weigh whether consumers would be willing to pay more for their products before they make a change.