I saw this commercial yesterday and had to do a double-take. Played it back on YouTube just now, and yes, indeed, this exchange really did occur:
"Amy," Nutrisystem Success Story: I can take care of the things that need to get done!
Marie Osmond: Including yourself.
Amy: Including myself.
[chuckles all around]
Wow. It's all there, starting at about 1:49, and it almost justifies what they've done with the "Substitute" riff.