In the luxe dining room of Del Posto, one of New York’s most heralded and expensive Italian restaurants, one-third of the tables on any given night will have at least one gluten-free diner.

Mark Ladner, the restaurant’s chef and widely considered to be one of the best pasta cooks in the nation, knows it is a remarkable number. Gluten, the protein in wheat that gives dough its elasticity, has been a key ingredient in his culinary success. But Mr. Ladner also knows that gluten-free dining remains a big and growing business, so he offers each of his pasta dishes, down to his 100-layer lasagna, in gluten-free form.

Similar gluten-free dishes, like pasta made with rice and corn starches and chewy focaccia, are woven into the menus at all the restaurants owned by Del Posto’s proprietors, Mario Batali, Joe Bastianich and Lidia Bastianich, Mr. Bastianich’s mother. “It really has become a thing, and I don’t think it’s going to go away anytime soon,” Mr. Ladner said.

A decade ago, few people other than those with celiac disease, a digestive condition, knew much about the health implications of gluten. But today, if you aren’t gluten-free, you likely know someone who is or is trying to be. The style of eating has become a way of life for many and a national punch line for others. More than a quarter of Americans say they are cutting down on gluten or eliminating it entirely. Optimistic researchers predict the market for gluten-free products will hit $15.6 billion by 2016. The Food and Drug Administration has noted the diet trend as well, and passed new labeling laws for gluten-free products to take effect in August.