Yeah, my friends and I also learnt the hard way - we ended up stuffing ourselves at breakfast and hoping to last the day! We never ate in the food court, because by the time a panel/event ended, the hot food had gone

We lucked out when a friend found £20 on the floor after the last party and blew it all on chips because we were that starving!
This time we're bringing various pot noodle-y type things for the hotel room - anything that can be made with just boiling water! We also do a pre con shop - things like biscuits, cheese sticks and crisps can be life-savers to just pop in a bag for when your at a con.
There is a burger king if you take the monorail towards the airport, and I hear you can take a bus into town where there is a tesco express I think. Things like the frankie and benny's and wetherspoons open at stupid times, so they're not really worth mentioning.
So...PREPARATION IS KEY!