Dauntless are given awesome chocolate cake and other foods, like hamburgers.
Candor is known for their ice cream and probably also have good food.
Erudite citizens are given fizzy drinks and nourishing food.
Abnegation even are fed normal food, even though it's pretty bland.

Then you've got Amity.
Who are given drugged water and bread.
I feel for Amity.
I mean, who came up with this system?
Johanna: Our citizens aren't happy enough
Johanna: LETS DRUG THEIR FOOD STORAGE AND WATER SUPPLY!

You'd think Amity wouldn't be as stable . . .