A flavor to beat the rest

Fluttershy's always been a healthy pony, eating only what she needed too and indulging herself very little, allowing her to maintain her slim figure despite her lack of exercise. This changes however when Pinkie makes a new pastry that makes Fluttershy's taste buds sing like none could before. Now she's making more and more trips to Sugar Cube Corner to feed her new craving, not helped by the fact that Pinkie has permission to discount treats fo her friends. Not one to have ever cared about her personal image outside of basic hygiene, her softening body goes unnoticed by her while Pinkie just finds it amusing and encourages her behavior.