It isn't even close, says Slate's Jennifer Reese. It's "America's Test Kitchen," the PBS show from the staff of Cooks Illustrated magazine.
You will learn more about food—what's wrong with domestic feta, why you should buy frozen shrimp, that anchovies lend flavorful glutamates to your beef stew and powdered gelatin silky richness—in one 30-minute episode of Christopher Kimball's playful series than you will in the complete oeuvre of Giada Di Laurentiis.
Nonetheless, she goes on to review the other TV food shows.