Her weight gain journey ends here but from her pose, you might not see much of a difference without comparing her to other ponies in her pose that I've drawn. Card info:
My Chubbiest Pony Rainbow Dash
LIGHT/Chubbiest Pony/4/ATK 0/DEF 2800
This card cannot be Normal Summoned or Set. This card cannot be Special Summoned except by Tributing 1 "My Chubbier Pony Rainbow Dash". this card cannot be destroyed by battle (with Damage Calculation"). When this card is attacked, your opponent takes damage equal to his or her's monster's ATK during Damage Calculation.
Secret Rare