My advice: write down everything you eat. It's amazing what that "self honesty" can do for you. (Do you really want to have to confess that doughnut? I thought not.)
Alton BrownWhat happens is that in each clump you've got the gelatinization of starches, which happens very quickly at the surface of the clump and it kind of forms a protective skin around this dry hunk of flour.
Alton Brown