MSG: Friend or foe?

And who isn't thinking about Monosodium glutamate?
My friend Rachel was telling me that she ate some Chinese food yesterday and, though she checked for MSG signs in the restaurant, still ate it by mistake. Apparently she can really tell when she's eaten it: She gets that bloated feeling; and she said it's still lingering today.
My reaction: I feel full quickly as I'm eating this type of food, but then not long after--within a few hours--I get incredibly hungry. Rachel, a nutritionist, says that comes from the MSG.