Festival food!

-- Pita bread, flatbread or tortillas (doesn't squish or dry out as fast as sliced loaf bread)
-- foil pouches of tuna or chicken (Chicken-of-the-Sea, BumbleBee, etc.) not as messy as canned. The smoked salmon, teriyaki salmon and lemon-pepper marinated tuna are very good. Great in flatbread for sandwiches or mixed with greens for salads.
-- cans of V-8 juice. I don't mind it at room temp and it's a good source of salt and potassium in hot weather plus is a full serving of veggies.
-- bags of mini-carrots. These hold up well for several days w/o refrigeration. I call them "roughing it toothbrushes" because nibbling on a few after a meal helps remove food stuck to your teeth and makes your mouth feel cleaner.
-- wax wrapped mini-cheeses like Baby Bel and the individually packaged sticks of mozzarella string cheese will hold up for quite a few days.
-- individual peel-top packs of applesauce and diced fruit
-- banana, nut or zucchini bread is good for breakfast.
-- apples, avocados, grapes, oranges
-- summer sausage or hard salami (can safely go without cooling for several days)
-- cans of german-style potato salad (it's made with a vinegary dressing and bacon bits, add cut-up summer sausage and diced sun-dried tomatoes and it's a tasty and filling casserole "salad") Be sure and bring a can opener if this isn't pop-top
-- canned or jarred 3-bean salad.
-- plastic bag of pre-shredded "broccoli slaw" (in the produce section of the market). Holds up better for several days than lettuce and makes a good crunchy addition to pita bread or flatbread sandwiches with the foil-packed fish or chicken. Or toss with ranch dressing for "cole slaw" (bring the individual packets of salad dressings like you get with take out -- these are good for veggie dip too)
-- juice boxes of real juice -- orange, grape and cranberry, for breakfast.
-- hard cheeses like swiss, asiago and cheddar, stored in plastic tubs. Most cheeses are fine for several days w/o refrigeration. Enzymes in them inhibit spoilage. Bring a small grater to shred the cheese for sandwiches and a folding camp knife to slice it.
-- several types of tasty whole grain crackers like Kavli or Kashi.
-- I like canned fish such as sardines and smoked baby clams on crackers but some people may not care for them (and I admit they are rather smelly so you need to have a trash disposal place that's away from people who would be grossed out.)
-- lots of oatmeal raisin cookies, also good for breakfast
-- hard-boiled eggs (eat them within the first day or two while the cooler is still chilling reasonably)

info not from my head but this person's:
https://ca.answers.yahoo.com/question/index?qid=20090625183757AABMFiA

Download festival then.

Take a gas canister fired grill. They aren't allowed but you'll get it in. I've been going for years and have never had a problem.

Food wise. Stop off at asda close by and buy burgers, sausages, cheese squares, bread rolls, crisps, chocolate, pot noodles, Chinese instant noodles.

I don't know if you've been before but we always end up camping too far away to be bothered walking back. So its fill up in the morning, get smashed, eat everything in sight at the evening/night from the food vans in the arena (there's a pieminister, enough said) then go back to the tent and drunkenly cook food.

Basically go and enjoy some awesome rock/metal without worrying about food for a few days.