The most ponnds you can loose at once is 3. So I don't really think there is a fast or easier way. And being fat is only one part of the game. You have to have the meter really high to win too.
Could someone tell me how I can keep playing the games? My tama keeps saying no even when his happiness hearts are at 2. I don't wan't to give him treats to play and disciplin doesn't work either!