Carpal tunnel, bad backs, hunched shoulders: If you're a nine-to-fiver stuck in the office all week, you're probably well-acquainted with the aches and pains that come with cubicle forest.

And, unfortunately, we've got some more bad news to add to your list of daily-grind woes: According to a new Career Builder study, 41% of Americans will gain weight as a result of their desk jobs. The good news? Gaining weight at work is entirely preventable with a few key changes to your routine.

Use these three tips from Lisa Clark, M.D., author of Lighten Up, America, to identify common and correctable causes of workplace weight gain.