I'm about 6foot 3/4 and really wanted to get in shape when I was about 14stone. I lost 2 stone in a couple of months eating around 1900 calories a day. That's worked out using BMR to work out how many calories I'd burn per day without doing anything then factoring in my activity level. (Google Harris Benedict equation) Then I took off 20% of this amount to ensure that I was working at a deficit (burning more calories than I was consuming)