>>29404720Certain Pokemon get fat when fed treats, and especially Rare Candies, this makes them slow, but raises their defense.
Not every Pokemon can gain weight, like, you can't make a Geodude or Honedge fat - but any animal like pokemon like Pikachu, Gengar, Goodra, etc can fatten up.
There is now a Sumo League, where the strongest, fattest pokemon compete in special battles to become Yokozuna. (There is only one weight class, so for a Rattata to qualify, they have to become as large as a fat Snorlax)
