"You use a average of about 3200 Kcal a day...."

I don't use anywhere near that amount, and if I started eating enough to supply that I'd soon need a whole new wardrobe!<img src="/images/graemlins/grin.gif" alt="" /> I use 2000-2200 per day tops, less if I'm sedentary. I think you'll find it will vary widely depending on age, sex, fitness level, etc.