Healthy eating has gotten complicated. Fresh fruits and vegetables pack the produce aisle as never before. And new food products with added health benefits are being introduced all the time. Yet the food supply, and the agricultural system that supports it, has become increasingly criticized for its impact on the waistlines of millions of people in the United States.

“Agriculture and conventional food systems have provided the basis for long and healthy lives, and much of that improvement can be traced to healthier diets,” says UC Davis plant sciences professor Alan Bennett. “At the same time, we are faced with a growing critique that conventional food...