The food on the Isle is mainly leftovers from Auradon. There is also a small supply of fish which is the only fresh food you can get on the Isle. The lack of sun and general quality of the Isle stops most things from growing and the little area of the Isle that can grow something is controlled by the Hearts. Residents rely on Auradon entirely for food, this means that all the food they do get is best it's best or barly edible.
The food is sent on the barges and mixed up between all the other trash on them. Things like stale bread and moldy fruit, stuff that Auradon doesn't want. The other option is eating rats or seagulls of which there is plenty around the Island.
Due to the large population and the fact that to food they are sent isn't always edible, people often go hungry.
Choice of drinks is also limited, there is one freshwater spring in the small hills by the Animal Quarter. Coffee can be made from old beans and filters, there is very little milk on the Isle it is mostly black coffee. They reuse teabags to make tea, and people will squash inedible fruit to flavor the water, plants are also blended in drinks to try and make smoothies.
Alcohol is the other option when it comes to drinks. Residents use fermenting fruits to make their own alcohol. While it isn't very good it is very strong. People on the Isle brew very potent alcohol. There isn't any drinking age so many kids and teens drink. Most of the older kids have been drinking awhile because they didn't have anyone telling them not to, but they try to stop their younger siblings from also becoming alcoholics.
Overall food on the Isle is bad and not for the weak stomach. Food is either cooked in restaurants or open fires in the streets, most things that are sent over has already been cooked or can be eaten raw so very few people have stoves in their houses. There are very few stoves on the Isle and the few that are there are reserved for the shops that's jobs are to feed the Isle residents.