Dante's father from Dante's Inferno. Besides being a Jerkass to his son, he was a complete pig who wasted all of his family's money on wine, women and song. Predictably, when Dante encounters him in Hell, he's become a demon of Greed.
The Mad Bomber, Fatman, from Metal Gear Solid 2, probably deserves mention here as well. Supposedly, his obesity would leave him practically immobile, if it wasn't for his nifty in-line skates... and besides, his taunt makes for the perfect header quote. "Laugh, and grow fat!" Oddly enough, he isn't called "Fatman" because of his bulk. His codename is based on the "Fatman", the atomic bomb that devastated Nagasaki in WWII.
The mayor of Lilligue in Grandia II is one of these. But then, he has been possessed by the tongue of a demon-god, so....
Pope Zera, a boss with animated jowls, undergoes a Face-Heel Turn by the end.
Sturrock the Meat King, your first target from Hitman Contracts. His perverse sexual proclivities complement his sizable mass, making it clear that he is evil and unsavory in every possible way.
King Dedede, recurring nemesis of Kirby. The two often end up in a battle over who gets to eat more. This is even the whole point of Gourmet Race, one of the games in Kirby Super Star.
Dapang, Wong's Dragon from the John Woo game Stranglehold, who is more of a former sumo-style deathmatch fighter than a true "glutton." Tequila even makes a crack about him the first time they meet before promptly being shoved into a chair by him for Wong's meeting.
From Overlord, there's Melvin Underbelly, an embodiment of gluttony. He's so fat that, when you encounter him again in the Bonus Level Of Hell, you use him to play both golf and Breakout...
No More Heroes: Assassin No. 3, Speed Buster. Despite her apparent vagrancy...
Sonic the Hedgehog: Dr Robotnik/Eggman is usually portrayed as this to excuse his gimmicky shape, but we've only ever seen him eat something once in the games. However, it involves him eating a submarine sandwich in under two bites, so it has some merit.
Mr. Luggs from Luigi's Mansion. You can hear his eating from the other side of the mansion, he shoots fire at Luigi and apparently ate himself to death by the age of 30. As the description says: He prefers all-you-can-eat buffets to three meals a day. He ate himself to death but still wasn't satisfied.
Borgan from Lunar: Eternal Blue. So fat he apparently has to have corridors greased to pass through them. Additionally, there are pictures of various characters in-game called bromides, and they usually show people in an attractive pose. Borgan's is bathtime.
Tengai Makyou IV features Madame Appetit, who leads a bizarre cult of gluttony out of Tombstone, AZ. She also proves to be an Acrofatic.
Governor Phatt is the fascist dictator of Phatt Island in Monkey Island 2: LeChuck's Revenge. It's redundant to mention that he's, by a bizarre coincidence no doubt, fat and is shown constantly (even subconsciously at times, it appears) eating whatever it is that's shoved down the tubes that lead to his bed that he never leaves?
The monstruous demon lord Horkos from Shin Megami Tensei: Strange Journey. Often eats his own underlings. Ate dozens of humans during his initial rampage. Wants to consume the entire world.
Not to mention his humble abode, Sector Carina of the Schwarzwelt. The entire dimension is modelled after a titanic shopping mall, with conveyor belts churning more and more food and luxury items, which are never enough to sate Horkos' eternal hunger for more.
Cursery's version of Humpty Dumpty was an aristocrat cursed with a ravenous appetite after Mother Goose gifts him with a magical (actually cursed) fruit.
Each of the Psychopaths in Dead Rising 3 correspond to the Seven Deadly Sins. Gluttony is represented by Darlene, a Fat Bitch on a scooter who tries to hoard a buffet for herself and stabs a man to death with a large spork for eating some of her food.