It also presented an opportunity for the hospitality industry to make real headway in addressing a pervasive and costly problem. The United States generates 63 million tons of food waste annually, at an estimated cost of $218 billion, according to a 2016 report by ReFED, a group of businesses, nonprofit groups and government leaders devoted to reducing the nation’s waste. Of that, roughly 40 percent is estimated to come from consumer-serving businesses like hotels and restaurants.

Though no good data exists yet about how much hotels or their buffets specifically contribute to the overall waste total, the thinking is that hotels are an ideal place to raise awareness and change behaviors around sustainability issues, as they have for water conservation.

“If we can change the way food service happens in hotels, it has the potential to influence a lot of different hearts and minds,” said Pete Pearson, director of food waste at the World Wildlife Fund. Thanks to a grant from the Rockefeller Foundation, Mr. Pearson is working with Hyatt, Ideo and others to develop a list of best practices for the hospitality industry to combat food waste.

By targeting buffets, Hyatt and Ideo are zeroing in on a hotel staple that by definition oozes excess. The question is why that is so, and what can be done to rein it in without shortchanging guests.

This is potentially tricky territory. For starters, hotels are loath to do anything that might upset guests. Ideo discovered that one key contributor to the food-waste problem is a fear of not having enough food, and so hotel personnel and conference organizers both inflate expected head counts to guard against any shortage. At the same time, guests pile their plates high to avoid going back for seconds, and to ensure that they get enough of the dishes they want.