Big Eater/Newspaper Comics

In the comic strip Blondie, Dagwood constantly eats comically large sandwiches. He's so well known for it that his name has entered the dictionary meaning "a thick sandwich filled with a variety of meats, cheeses, dressings, and condiments." It's also a popular name for sandwich shops in the midwest. In Belgium, Dagobert (the French name for Dagwood) is the name of (thick) sandwiches made from a half French bread filled with lots of ham, cheese, salad, tomatoes, carrots, mayonnaise and sometimes onions.
Peter and Roger from FoxTrot; while Peter does this year-round (even eating groceries before his mother has gotten them to the parking lot of the store), he and his father really shine on Thanksgiving. Partly subverted because Roger is already a little chubby. Also partly subverted during those times Peter is deliberately trying to gain weight (and failing miserably).
Jeremy in Zits. Truth in Television, as anyone who knows teenaged boys can aver.
In one arc of Bloom County, as seen [1], Oliver went through 176 Dominos Pizzas to stay awake while building his Electro-Photo Pigment-izer.

Garfield-To the point that a few times, his legs couldn't even reach the ground.
Billy Bunter, a British comic strip character who first appeared in 1908.
Beetle Bailey has Sarge and Cookie.