A well-known campaigner for sustainable foods, Barber said during a visit to Paris that the ban was a distraction from real efforts needed to improve eating habits.
"It's a bad idea that is not going to do anything," he said.
"We are talking about a whole food system that is really in trouble. To talk about foie gras is a detail, it looks more like a commercial decision," Barber said.
The 43-year-old, named outstanding US chef in 2009 by the James Beard Foundation, owns several restaurants including Blue Hill in Manhattan and is a member of the US presidential Council on Physical Fitness, Sports and Nutrition.
He added however that he does not serve foie gras on his menu as he has been unable to find enough produced without force-feeding.
California banned foie gras -- fatty liver made by force-feeding ducks or geese with grain -- on July 1st in a move hailed by animal-rights activists but denounced by the industry in France as a violation of international trade rules.