Think of the spaceship like a cruise liner. All or most passengers will likely have three meals a day included in their tickets. I imagine Homestead don't really need passengers dying of starvation, so everyone gets fed and watered, except some get fed better than others.
If you skip to around 14m30s into the film when Jim is bashing away at the coffee machine, there the following exchange between the Jim and the machine:
Jim: "I want the mocha cappuccino extreme, bill my room please".
Machine: "Food can be purchased in the ship's...".
This suggests there's somewhere else on the ship where you can pay for better food or luxuries that aren't included in the cost of the ticket. In fact, later in the film, at around 40m:30s, when Jim meets Aurora for his "date", the following exchange takes place when Aurora admires Jim's sartorial upgrade:
Aurora: "You went shopping"
Jim: "I went shop lifting"
This suggests there are on-board shops, and Jim broke into one of them to obtain his suit. This would lead us to believe that if you have enough credit you can buy what you need, including better foods.