I know that meals make your tama. gain 1 pound and snacks make them gain 2 pounds! The only game I'm positive doesn't make you lose weight is shape. OR you could switch to just starving them...... it's not a good idea 'cause they might die. It happened to me!
Sorry just remembered something: your tamagotchi can never get heavier than 99 pounds!!!!!! My tamagotchi was 99 pounds, i fed it and it never got heavier when I chaecked the weight!!!!
I've noticed this too because i have a V3 and she is 1yrs old && she weighs only 17lbs && i have a V4 that is 0yrs old && he weighs 21lbs I play games very often but i agree with the others i think you do have to win the game to lose a good amount of weight because when i win the Jump roping game i lose 3lbs but if i just play && don't win i only lose 1lbs!