Only the fairy Gratitude Crystals are useful, I uploaded a gateway cheat for those on fort42Not sure if someone already did this:
savegame offsets for fairy food:
base offset: 233A
max amount: 255 (FF)
apparently there are 132 different foods in the game...
additional offsets for the bronze foods (offset +1 = silver / +2 = gold)
000 Weird Egg
003 LonLonMilk
006 Odd Mushroom
009 Deku Nut
012 Magic Bean
015 PumpkinSoup
018 Sacred Water
021 Life Tree Fruit
024 Light Fruit
027 Stamina Fruit
030 Water Fruit
033 Mushroom Spores
036 All-Purpose Bait
039 Elixir Soup
042 Hyoi Pear
045 Ordon Goat Cheese
048 Great Fairy Tears
051 Greengill
054 Ordon Catfisch
057 Hyrule Bass
060 Hylian Pike
063 Reek Fish
066 Hylian Loach
069 Skull Fish
072 Bomb Fish
075 Chu Jelly
078 Bee Larvae
081 Chateau Romani
084 Bottled Water
087 Hot Spring Water
090 Rock Sirlion
093 Meat
096 Carrot
099 Ember Seeds
102 Scent Seeds
105 Pegasus Seeds
108 Gale Seeds
111 Mystery Seeds
114 Gratitude Crystal (Red)
117 Gratitude Crystal (Blue)
120 Gratitude Crystal (Orange)
123 Gratitude Crystal (Pink)
126 Gratitude Crystal (Purple)
129 Pumpkin