Darron Cummings/Associated Press
Obsession: His diet.
He might not be the dominating pass-rusher that he used to be early on in his career—age and mileage tends to do that to a guy—but San Diego Chargers linebacker Dwight Freeney, 33, is still a freak.
At 6'1" and 268 pounds with the ability to run a 4.5 40-yard dash, one reason he stays in such great shape is because of what he puts in his body.
Rather than count calories or look at nutrition facts like most folks, Freeney just sticks to what he knows works—which is a bit compulsive, but hey, the proof is in the results.
Per Sports Illustrated, via Pop Sugar:
His diet makes supermodels look indulgent. From the Wednesday morning before the [AFC championship] game to kickoff that Sunday afternoon he ate beef and pinto beans and nothing else, not even for breakfast. He drinks only grape juice, water and occasionally tea as a treat. If he goes to a restaurant he brings his ingredients with him and instructs the chef on how he wants it prepared — no oil, no pepper, no garlic, no garnish, no powder and certainly no pan spray.