First thing to remember is that most times you will have no fridge. A cool box lasts only a day or two at summer heat, so don't take anything that will go off that you can't eat on day one.
I like to take prepacked (individually wrapped) pastry style snacks like Pitch or croissants for breakfast.
I take some eggs if I plan to cook, also soft noodles to stir fry with sauce. Baked beans of course, soup, chilli and packs pouched rice.
Not everyone wants to cook of course, although Camp Bestival does allow small stoves.
"Are Chinese lanterns, flares, fireworks or campfires allowed?
No, we have a no naked flame policy at the festival and in the campsite. Fires, flares, fireworks etc will extinguished by our festival fire service. HOWEVER, there are designated cooking areas in the campsite where you'll be able to go to use small BBQs and stoves to cook food."
You might want to plan and take a packed lunch for the first day, a great idea while you are struggling to get tent up etc to know you have lunch all ready.
Other cold food snack ideas include, crisps, nuts, babybel cheese, raisins or other dried fruit, biscuits, individual cartons of juice, cans of coke etc
Oh and if you want to make tea or coffee, take coffee bags as well as tea bags, (no glass including jars allowed on site) and sugar LUMPS (less mess, avoid spills in and out of the tent!) and take powdered milk or individual long life pots
Definitely take snacks and drinks if you have kids. Queues will be long at exactly the moment young Tarquin wants a drink, you can bet on it! So save money, time and a tantrum. Be prepared!