Fueling the Flames

At first, Sokka dismisses it.
He notices, they all do, that Katara feeds Zuko less. A lot less. He notices that Zuko’s portions are often burnt and lacking any care, so even the little bit he does get is barely salvageable.
Sokka notices, but he doesn’t care.
(In which Fire Benders need to eat twice as much because they create their own fire. Based off Chapter 17 of "The One Where Zuko's Hair Matches Sokka's and Other Tales")