TV writers are desperate SJWs, generally, who will take every opportunity to insert some preaching. It's sad, because the show (which I do not watch, either) could be using this as an opportunity to point out that fat causes all kinds of fertility problems and that if you can't even put the fork down how are you going to raise a baby, but instead I imagine it's all "Poor lady, it's just bad luck that she's having so much trouble getting/staying pregnant." And if a character dares to mention that her weight is an issue they'll write her some kind of "epic" put-down speech that all the SJWs on the internet will rave about.