Just to expand on the answer a little, the flight gets catered for the outbound and return segments from the hub, and the FA's just switch out the carts and oven racks onboard with the return catering after the first segment. Depending on the length of the flight, the catering can be augmented at the outstation with bags of ice, depending on the arrangement. Short of that there are usually few differences, only one I've seen myself is that sometimes the desserts on 1,300+ mile double-catered return flights may be pastry-based instead of ice cream/sorbet, but that's been inconsistent.