Haha. Next time can train fishing can cooking liao. I will stock
food in bank.
Yea but maybe try not to waste good food during clan wars.
Use cheaper food like trout or salmon.
Use lobster/swordfishes for pvping(player vs player). There are
special worlds just for pking(player killing).You can check which
worlds at the world list. Their labeled Bounty Hunter World or have
a "TICK" below the skull. Don't worry, before you enter the world
they'll warn you its a PK world and you'll be fighting ppl around
your level only, so don't worry.
Unlike clan wars, you'll be risking all your items(runes
included) if you get killed. But you'll get loot when you kill your
opponent too. If you're lucky, you might get a corrupt item worth a
few million. 
Read more here...
http://runescape.wikia.com/wiki/PvP_worlds
http://runescape.wikia.com/wiki/Bounty_Hunter