Nothing makes the afternoon endless like the after-lunch slump. All you want to do is crawl under your desk (or into a closet or the backseat of your car) and take a nap. If you're tired of fighting the slump, here are some things you can do to prevent it from happening.
Instead of getting back on task after you eat lunch, get out and exercise instead. Even office workers can go for a quick walk inside (or outside) the office building. Those who work outdoors can do stretches and breathing, or walk up and down a flight of stairs for 10 minutes. You don't have to work up a big sweat, just enough to get the adrenalin going.