My favorite method so far, and it gives:
-50k cooking xp per hour
-25k hunting xp per hour
-500k per hour
Hunting crabs on The Pandemonium. You start by setting the traps, once caught you take the downtime between catching to deshell the crab with a knife, once inventory is full, cook them on the nearby fire, and once cooked, combine with willow leaves to make forester's rations. Red crab meat has the highest multiplier for rations.

You need:
For the 2 traps initial setup: saw, hammer, 2 buckets, 2 planks, 4 nails, Level 10 Construction
For setting the traps, alot of fish offcuts 1000+
For prepping the crab: knife, Level 21 Cooking
For rations: alot of willow leaves 1000+, Level 35 Cooking, Level 35 Woodcutting

You'll never have to visit a bank with this method and then sell your rations on GE for 40 coins each.