Rigorous isn’t a word I’d use to describe director Richard Linklater, which must partly explain why his fictionalized film of Eric Schlosser’s 2001 exposé feels to me like such a misstep. It’s as if Linklater hoped some of Schlosser’s scholarship would rub off on him, while Schlosser, who co-scripted with the director, went in for indie-movie cred. Well, they kind of cancel each other out; Fast Food Nation lacks both tastiness and nutritional value. It’s structured as a loose affiliation of lives adversely affected by the juggernaut of America’s meat-packing industry, and Linklater has enough touch to trick you briefly into overlooking its caricatures, but he tips his hand by not really taking them anywhere. Also, his customary loping pace feels patronizing here. What does it say that a cow-slaughter showpiece actually is the movie’s dramatic highlight? This isn’t raking muck so much as gently stirring it; all the insights feel warmed over, as if by heat lamp.