Green’s Dictionary of Slang

(US) a pot belly; thus adj. bean-bellied.

1842		Whip & Satirist of NY & Brooklyn (NY) 16 July n.p.: That bean-belly gent.
1884		St Paul Dly Globe (MN) 10 Feb. 8/6: Deacon Podd was unkind enough to remark: That bean-bellied olf ape can’t skate.
1892		L.A. Herald 24 Dec. 3/3: You never did see a horse thicken out as he has done [...] You’ll find it hard to get that big bean-belly off him.
1892		Salt Lake Herald (UT) 7 Dec. 8/2: Bill had a bean-bellied pony that would make after a buffalo like a hound for a hare.
[1900		Sun (NY) 1 July 6/4: ‘Bean-belly’ a great eater of beans].
1902		CopperEra Clifton, AZ) 9 Jan. 1/3: Fred W. Smith [...] was distinguished [...] by his peculiar appellative of bean belly, given [...] in recognition of his abdominal protruberance.
1915		Eve. Public Ledger (Philadelphia, PA) 30 July 8/3: [headline] Corpulent Policeman Shakes his fist Impotently at Urchins’ Cries of Bean-Belly‘.
1960		(ref. to c.1900) oral testimony in Lighter HDAS I 113/1: ‘You’re getting a regular beanie.’ It’s short for bean belly.
1968		G. Radano Walking the Beat 16: I take a good look at this guy. A monkey! he has a bean belly, a head shaped like a football.
2000		bearsnbuddies.com 🌐 Howard P. Potter, a 12" mocha color bear [...] wears a country woven plaid neck bow. Howard P. Potter has a big, full, bean belly and upper limbs for posing.
2002		Fetish Kingdom 🌐 You also get a bonus scene with Bean Belly Bust! This is the scene where I drink an entire gallon of water while you watch my belly grow more with each guzzle.