You must feed every type of food by itself, as well as combined in order to get the achievement. You might just eventually get this while going for S ranks, or you can keep track by writing these lists down, and crossing off each one you get completed.
Normal:
Beer
Cake
Cheap Wine
Cheese
Chicken
Dulvey Cru
Fruit
Garbage
Spice
Stew
Sugar
Combinations:
Baker Family Special: Garbage + Sugar
Cheese Fondue: Cheese + Stew
Cheesecake: Cheese + Cake
Fruit Beer: Beer + Fruit
Fruit Cake: Fruit + Cake
Spicy Chicken: Chicken + Spice
Sugar Cake: Sugar + Cake
Tom Yum: Spice + Stew