Yes, people usually come for the busty red head who gorges on candy, but that's no reason to think humour doesn't enter the equation.
In the very first strip, Lalia talks to Jane about her weight gain and wonders how much of a workout she'll get from digesting cookies.
At a party, a slightly drunken Lalia crushes on a cute guy named Stepehn from the Bake Club. She pulls him in for a hug, when suddely her dress gives way, knocking him to the floor as her belly bursts out of confinement.
Lalia: Stephen? Are you okay? I-I don't control it!
Jane explaining in great detail her recent actions on World of Warcraft. Lalia does her best to sound like she understands.
Lalia notices she finally gained some noticable weight and is utterly horrified and confused as to how it happened. Jane offers an [[[[Clipshow explanation.]]]]
After showing the most wanton of her gluttony in the entire series AND eating the two pies she made specifically for Thanksgiving, Jane finally loses it with Lalia and forces her to promise that she will only eat what is offered to her once she's at the table, something a startled Lalia agrees to. She had not bet on her mother being quite so excited to get such an appetite in her midst.
In Part 4 of Coming Apart at the Seams, Jane walks in to see Lalia with a massive girth, covered in milk and cereal flakes, and the entire kitchen covered in cereal boxes.