Davis, Irvine, Riverside and Santa Cruz were the first to do it, in 2008. Santa Barbara started it last fall, and UCLA is testing it now.

Now Berkeley is on board, joining its sister campuses and other universities around the country that have gone trayless — as in no more plastic trays in dining halls, in an effort to reduce waste and make food service more sustainable.

“It’s now the social norm. There’s a stigma if you get a tray,” said Rima Maher, a sophomore majoring in political economy, who was having lunch at Berkeley’s Crossroads dining hall on April 12 with just a plate, bowl and silverware in front of her.

“I don’t eat less because of it,” Maher said. “I’m not reducing waste. But it’s a positive idea, and it’s not much of a sacrifice.”

For students, trayless dining is a tangible sign of UC’s recently enacted sustainable food service initiatives that set goals for using products from organic or local sources, environmentally friendly practices and education on sustainability issues.

Trayless dining is intended to discourage people from taking more than they can eat, which cuts down on food waste and saves resources because there are no trays to wash. For people with disabilities or who insist on using a trays, they are available at central locations in dining halls that have trayless policies.

The first UC campuses to go trayless are reporting good results.

At Santa Cruz, food waste is down by more than 30 percent, saving nearly $500,000 in food expenditures and more than a million gallons of water a year, according to the UC annual report on sustainability.

Irvine officials say food waste per person is down 25 percent to 30 percent, while Riverside officials say they are saving 8,000 gallons of water per week.

Davis officials say waste volume is down 50 percent since the introduction of trayless dining.