In Antoine de Saint-Exupéry's The Little Prince (and its movie version) the aviator draws a boa constrictor with an elephant inside. Since the back of the snake is the one he draws as distended, it gets mistaken for the drawing of a hat the first time he shows it to other people.
In Lois McMaster Bujold's Mirror Dance, Miles Vorkosigan's clone brother Mark binges on combat rations for two weeks, bringing his weight up too in a half-conscious effort to separate himself from his progenitor. Which looked alarming enough given they both are under five feet tall. And then it goes From Bad to Worse.
A verse by Shel Silverstein: "If I eat one more piece of pie, I'll die! If I can't have one more piece of pie, I'll die! So since it's all decided I must die, I might as well have one more piece of pie. MMMM—OOOOH—MY! Chomp—Gulp—'Bye."
Children classic Winnie-the-Pooh does this. Pooh eats so much he gets stuck in Rabbit's burrow.
Noncomedic example: According to the Zombie Survival Guide, since zombies don't digest human flesh, they can end up with distended stomachs fairly quickly.
Poor Stuffy Pete ends up with one after guilt-tripping himself into eating two huge Thanksgiving dinners in succession by mutually unaware benefactors in O. Henry's "Two Thanksgiving Day Gentlemen".
In Charlotte's Web, when Templeton the Rat returns from stuffing himself on the bountiful discarded junk food at the county fair, the author describes him as "big around as a jelly jar."