sorry, been xmasing.
You seem to be laboring under the illusion that Jack (who's last name is indeed 'Spratt') could 'eat no fat' due to a medical condition. You are 100% incorrect. Jack can 'eat no fat' because he was told that if he didn't lose at least 100lbs he would be dead in the next 3 years. That's why they call him 'fat jack'. Anti-Jill antagonists claim that Jack & Jill licked the plate clean, but this is also a falsehood spread by Jacks unethical legal team. Truth is, he used to give the empty plate to Jill, and she would have to lick it clean. This was her 'meal', and this abuse went on for years. It's one of the main reasons that Jill's parents are so worried about her weight. She's lost at least 30lbs since they hooked-up together. The only chance she has of a decent meal is when Jack has one of his 'turns' and puts her in the hospital. There she gets three meals a day, which she has to eat through a straw due to how Jack fxcked up her face.
One things for sure - If Jills dad ever catches up with Jack, he's toast.