S4, E7: Ron goes on an all Bueno Nacho diet to prove that the Food Pyramid is a horrible health conspiracy, but when he starts to grow too big for his britches (literally!), Kim thinks it may be time for him to admit defeat. During a mission, Ron falls into a vat of serum that slowly changes him into a 15 foot behemoth and the only way to stop him is for Kim and the Tweebs to trick him into eating healthy food from the Food Pyramid!