Chef Roy Choi showed talent as a teenager, attended the Culinary Institute of America, and made his name in restaurants. But it was selling Korean tacos out of a food truck in 2009 that put him on the food map. In a 2013 talk at Ren Redzepi's MAD Symposium, he challenged chefs to not just "cook for rich people" and to find ways that they could feed more than just the privileged.