Let down! Wii Fit isn't one hundred percent exactly as Nintendo's Shigeru Miyamoto pictured it. Instead of just weighing people, Miyamoto wanted it to weigh pets. According to Newsweek:
...Nintendo design boss Shigeru Miyamoto had wanted to include a mode that would allow players to weigh their pets. He wasn't able to include it in the Japanese version, but in the North American version, available May 19th, players will receive a message informing them that if they weigh themselves while holding their pets, then weigh themselves again separately and subtract the two, the difference will tell them how much their pet weighs.
No word whether Miyamoto also hoped to have balance board mini-games for pets.