Starscream is a Seeker, formerly near-nobility, and recoils from the very idea. Probably sneers and calls everyone involved “disgusting savages”. 

Knock Out won’t touch drained energon or protoflesh as a meal, something about his systems being too refined for such garbage, but will take a body apart just out of general him-ness.

Gravescratch eats just about anything he kills, including people. Definitely including people. And one of the Functionalists, or so he claims. He can digest metal and protoflesh, making him the only person who’s never gone hungry during the war- there’s always scavengers to be had. To him, the entire planet is edible, and so are limited amounts of organic things.

Blackspark doesn’t tend to eat people, since germs, but hunts and eats small animals for food. He’ll chew on people if he’s hungry enough. 

Shockwave is practical enough to do it, but prefers to process the energon first, deadpanning something about potential infections. He probably has a portable energon filtration system in subspace at all times for just that situation. Can’t eat the fleshy bits because he doesn’t have any teeth. 

Crucible (most people haven’t met him, short-but-solid mech whose alt is his namesake) isn’t proud of it, but he’s eaten corpses. Mostly out of fear- he has very high fuel needs, especially if he’s been using his alt mode, and panics at the potential of starving. Panics enough to overcome his squeamishness at the idea and be caught chewing on someone’s fuel pump. Unlike the others on this list, he feels bad about it, despite his usual pragmatism. Different upbringing.