In case anyone still thinks Twitter is all about what we ate for lunch, a look at Twitter’s top trending topics in 2009 should put that to rest for good.

The Iran election was the top trending news topic, with swine flu, Gaza, Iran, and Tehran rounding out the top five. #Iranelection was also the second most popular hashtag.

Twitter broke down trending topics in seven categories, including people, technology, and sports. Twitter’s chief scientist, Abdur Cowdhury, terms the trending topics “an interesting time capsule of what was happening as this decade came to a close.”

Other than observing the absence of lunch meats, anything you would add to this list?

Photo by Gary Burge. (Flickr).