[Spike realises he totally said the wrong thing, and a panicked look crosses his face as he tries frantically to backpedal.]

Oh, uh...I'm sure that's not the case! I mean, I'm pretty sure she'd know when she was running low or something and let you know, and then you could take her to a pokemon centre or something. I mean, it'd be like being hungry, you know? Everypony knows when they're hungry, and then she'd just have to replenish...

[Now he's just rambling in a rush, trying to ease Maka's mind.]