Ask a Physicist: How Much Energy is in Me?

"Game Maker" wants to know: I'm designing a fire-wielding superhero who uses his own body as fuel for his powers. How much heat energy would be created if a person were to burn off 50-100 lbs of fat in the span of 5 minutes? (Assuming he has the requisite "secondary superpowers" to avoid dying in the process). Oh wow, great question--and one that we should be able to answer using almost nothing but math!So first off, you'll want to keep in mind that a "food calorie"--or "Cal" spelled with a capi...