'The Bourne Ultimatum' star - who was given the honour last year by People magazine - joked the 20 to 30lbs he gained for Steven Soderbergh's upcoming thriller 'The Informant' may disqualify him from the position.
He said: "I think I lost my title."
The former heartthrob - who won an Oscar for co-writing 'Good Will Hunting' with close friend Ben Affleck - also revealed he really enjoyed piling on the pounds for the role.
He added to People magazine: "It wasn't necessarily that I needed to be fat. It was that I needed to be doughy. I just stopped working out and basically just ate whatever I wanted. I ate a lot of In-N-Out, a lot of burgers, drank a lot of beer and basically had a great time. When you're in your 20s you can do that kind of stuff. When you're in your 30s, it's a whole different ball game."
Meanwhile, 'Gone Baby Gone' director Affleck has been quick to poke fun at his porky pal.
He said: "Some things are just self-evident and don't even require making fun of. I mean, the man buys two seats on an airplane!"
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