The 48-year-old star - who has slimmed considerably after a new fitness campaign - said he couldn't stop himself.
In a webchat for MySpace, he admitted: "The two days before I went healthy I had 11 sausages, I couldn't stop eating them, I felt really ill, really bad and I had to lay there for a couple of hours, like a snake just trying to digest it."
He continued: "It was just after Christmas, a few days before I thought right, that's ridiculous. I think I hit 14 stone."
Gervais, who said he has been putting on weight since he was 29, is now committed to a healthier lifestyle. And he said he had lost a stone since embracing exercise and "turning his life round at the last minute".
The comic, promoting new film Cemetery Junction, is now writing a new TV project with Stephen Merchant.
"We're writing a sitcom together, written and directed by us and it's called Life's Too Short and it features Warwick Davis. It's a cross between Extras and Curb your Enthusiasm and One Foot In The Grave but with a dwarf. That is out and out funny."