Cereal Girl is the name of a girl from the purpleberry puffs cereal ads. She gained weight from the cereal and it's possible she has diabetes.
Cereal Girl: Mom why is there orange in my purple berry puffs? Cereal Girl's Mother: As an active mom I care about these things I'll check the box while you start eating.
Princess Purpleberry: Now my Purpleberry puffs have loquat flavored orange berries!
Cereal Girl: Two colors, wow!
(Scene flashes and she gains weight)
Zoidberg: It's a small part of this girl's breakfast!
(bubble he's in pops)
Zoidberg: Whoa!! (he falls in a bowl full of milk)
(Cereal Girl and her Mother laugh)