How many calories per day for a 12-year-old girl or boy?

The number of calories per day for a 12-year-old depends on such things as body weight, health, and level of activity. It also depends on whether the 12-year-old needs to:

• lose weight
• gain weight
• maintain weight.

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As many as they like, but try to burn off the same amount of calories than you have put on. It doesn't really matter how much they have or how heavy they are at such a young age.