Enlarging or modifying an animated character

Hello everyone! I ran into the following problem: I need to increase (not scale) / modify the character, i.e. make it more or less depending on what he collided. My character is animated, he runs, jumps and etc. To better understand what I want to do, you can check the Fat Pusher game for android (where the player gains weight when he eats and drops it when he pushes the load)

I will be glad to any suggestions and solutions to the problem