Sugar and teeth

[Malleus, Incus, Stapes!]

Since the amylase in saliva breaks down sugars, why is sugar the worst thing for teeth? Why not fat or protein, which presumably sticks around longer?

[Colophon]

Amylase (http://en.wikipedia.org/wiki/Amylase) breaks starches down into sugars. Bacteria feed on sugar and produce acid, which erodes tooth enamel.

[Malleus, Incus, Stapes!]

Ah. Thanks.