What is meat for in Game of Thrones: Dragonfire?

Meat is used to feed your dragons, which raises their Reign Level. It's an alternative to combat: instead of earning XP by killing enemy troops, you give meat to the dragon to push it forward directly.

Leveling a dragon raises its 4 stats (Strength, Instinct, Intelligence, Initiative) and the max army size it can lead.

Watch out: leveling through meat is capped per campaign stage (a ceiling that rises as you progress), and Reign Level resets every reign.

So meat, like the basic resources, is throwaway: use it to boost your key dragons fast during the reign, not to build up a stockpile.