I got all my info from: http://bulbapedia.bulbagarden.net/wiki/Gummi
Gummis (Japanese: グミ Gummi) are consumable items found in Pokémon Mystery Dungeon. Gummis come in a variety of colors, and have varying effects based on where they are applied. In all instances, eating a Gummi will increase a Pokémon's IQ, allowing it to learn more IQ Skills, with better-tasting Gummis increasing the value by a greater amount.
Black Gummi: A food item that permanently increases the IQ of a team member. Dark-type Pokémon like it most. It also somewhat fills the Pokémon's Belly.
Blue: A food item that permanently increases the IQ of a team member. Water-type Pokémon like it most. It also somewhat fills the Pokémon's Belly.
Brown: A food item that permanently increases the IQ of a team member. Ground-type Pokémon like it most. It also somewhat fills the Pokémon's Belly.
Clear: A food item that permanently increases the IQ of a team member. Ice-type Pokémon like it most. It also somewhat fills the Pokémon's Belly.
Gold: A food item that permanently increases the IQ of a team member. Psychic-type Pokémon like it most. It also somewhat fills the Pokémon's Belly.
Grass: A food item that permanently increases the IQ of a team member. Grass-type Pokémon like it most. It also somewhat fills the Pokémon's Belly.
Gray: A food item that permanently increases the IQ of a team member. Rock-type Pokémon like it most. It also somewhat fills the Pokémon's Belly.
Green: A food item that permanently increases the IQ of a team member. Bug-type Pokémon like it most. It also somewhat fills the Pokémon's Belly.
Orange: A food item that permanently increases the IQ of a team member. Fighting-type Pokémon like it most. It also somewhat fills the Pokémon's Belly.
Pink: A food item that permanently increases the IQ of a team member. Poison-type Pokémon like it most. It also somewhat fills the Pokémon's Belly.
Purple: A food item that permanently increases the IQ of a team member. Ghost-type Pokémon like it most. It also somewhat fills the Pokémon's Belly.
Red: A food item that permanently increases the IQ of a team member. Fire-type Pokémon like it most. It also somewhat fills the Pokémon's Belly.
Royal: A food item that permanently increases the IQ of a team member. Dragon-type Pokémon like it most. It also somewhat fills the Pokémon's Belly.
Silver: A food item that permanently increases the IQ of a team member. Steel-type Pokémon like it most. It also somewhat fills the Pokémon's Belly.
Sky: A food item that permanently increases the IQ of a team member. Flying-type Pokémon like it most. It also somewhat fills the Pokémon's Belly.
Wander: When used, this item causes the user eyes to become gunky, and the user gets Blinker status. A Lookalike Item for Wonder Gummi, so be careful!
White: A food item that permanently increases the IQ of a team member. Normal-type Pokémon like it most. It also somewhat fills the Pokémon's Belly.
Wonder: A food item with a curious texture unlike any other Gummi. It permanently raises the IQ of a team member. It also somewhat fills the Pokémon's Belly.
Yellow: A food item that permanently increases the IQ of a team member. Electric-type Pokémon like it most. It also somewhat fills the Pokémon's Belly.
http://bulbapedia.bulbagarden.net/wiki/IQ <-----That may help in understanding IQ.
