[kencausey]

I think the point is that the fermentation is taking place in an effectively closed system, there is no calorie input. The fermented fruit cannot possibly have any more caloric content than the original fruit, it has just changed form.

[postalrat]

Are you sure? Couldn't the energy be locked away in some form that can't be digested until it's fermented?

[morebortplates]

Exactly. Couldn't have said it better. :)