Pixie Pop(2004)

Gokkun! Pucho

Mayu, the daughter of a café owner, is unlucky in love until she meets “Puchou,” the magical fairy of beverages. Now, whenever Mayu drinks something, she transforms accordingly! Milk makes her grow large, water makes her invisible, pork soup turns her into a cute little piglet. But what will help her win the man of her dreams?

(Source: Tokyopop)

Note: Includes 6 extra chapters.