Wii Fit Plus' New features
The Pet Support System
This time Wii Fit Plus is able to weight your loved pets called, The Pet Support system. It can create an avatar for your pet, Enter information for your pet such as birth dates and use the Wii Balance board to weigh themselves and the game will let your pet excerice along with you. It is a fun way to exersice with your dogs or your cats.
Calorie Check
You can set a goal to your calorie your trying to archive and you can check the foods you have eaten and see how much calories it contains in each food. It is like the weight scale check on wii fit but instead it tells you about the calories, Dont worry you will still have the weight check system availble in Wii Fit Plus.
What are METs?
METs are "points" for your activity, eg. The Hula hoop excercise is worth 4METs. So the games calculate the calories you have lost with the METs you have earned today, your weight and duration of the time you've exercised.
eg. You have earned 4METs by doing the Hula hoop excercise for 30minutes and your weight is 150lbs
(METs)x(weight)x (time)x 0.48 (you need this number to calculate your calories you've burnt)
And the game will automaticly calculate how many calories you have burnt today.
*For the video about METs click the link below and check the Learn about METs section*

Source: http://wiifit.com/my-wii-fit-plus/#calorie-check