Mickey Mouse has appeared in over 250 comic publications around the world. While Donald Duck is more popular in comics, Mickey has been featured in comic books, magazines and newspapers, the latter finishing in the early 90's. Many of these comics have faded into obscurity, but information can be found in the Inducks database.
The Time-Flower Bamboozle (#22, 1972)
Morty, Ferdie and Pluto step on a scale. One of them seems to have gained weight beforehand.
Pluto is too fat, so Mickey puts a "Do Not Feed" sign next to him.
A fortune cookie from a scale causes Minnie to gain weight.
Minnie gets nightmares of Mickey fattening her up after having a midnight snack.