She holds her fat weird and looks like she is pregnant or has worms. She's def got that pear body shape lmao. Gotta start with reducing food and using a slow feeding bowl and then if she still continues to gain weight, I'll have to put her on a diet.
You named her Jelly gotta expect a jellyroll. For faster slimming, try to give her extended playtimes, especially before feeding, and encourage Wacky Kitty Time when she's interested like after using the litterbox and in the middle of the night.
Real world case of nominative determinism right here