I'm close; Annie's lectures about the need to watch what you eat make Elly feel inferior.
Panel 1: We start off with Elly hovering over Christopher while handing him a ball; Elly's telling Annie's ankles that he's growing like a weed make me feel uncomfortable owing to the fact that Lizzie's head is attached to her left ear like a gigantic goiter.
Panel 2: As she blends up some baby food, Annie says that's because she doesn't give him store-bought foods; she makes sure to make everything herself so she knows what he eats.
Panel 3: As she says that mothers who don't are ignoring some important factor, she's distracted by trying to figure out what Lizzie is looking for in Elly's purse.
Panel 4: Upon discovering that she found a cookie in there, Elly sheepishly states that it's from a reputable bakery.
Summary: Annie touched the whole thing off Monday by making Elly feel inferior because she could only manage to cook the slop John 'forced' her to; she's making matters worse by treating Elly like a peon because she can't be a supermom like her. This is why I've said that Elly needs to widen her family of friends; she could start by seeking out people who don't make her feel inferior.