I'm not even close; today's strip has John ruin everyone's appetite because he can't wait for Elly's cooking.
Panel 1: As eight-foot John looks on in apprehension, dot-eyed, button-nosed Mike asks Elly, who's stirring whatever she's cooking in the slow cooker, when supper will be ready; not realizing that by removing the lid, she's added to the time needed, she says that it'll be twenty more minutes.
Panel 2: John whistles to himself as he reaches in the cupboard; since Elly is tossing a salad with her eyes closed, she doesn't notice him doing it.
Panel 3: We next see him, Mike and Lizzie in front of the television MUNCH-CRUNCH-MFF-GULP-CRUNCH-SLUPP-GRUNC
Panel 4: They finish off the cookies just as Elly yells that SUPPER'S READY!!!
Panel 5: We next see them seated at the table looking askance at their plates of Elly's Yellow Surprise because they're too full to eat; since she didn't see or hear them devour the bag of cookies, she asks what the matter is because she thought they were hungry.
Summary: It's hard to say what precisely Lynn is going for here but all roads lead to John being as big a jerk as Phantom Space Man; either he's too greedy to wait for her cooking or too impatient to do so. In any event, you'd think that a dentist would know better than to load up on empty calories before eating.