Weight

Trying to figure out why I'm over weight, after watching the Nightline show last night - bashing fat people - I added up what I eat and drink in a day and I'm coming in right at or under 1400 calories. I just looked up on the fat caculator http://www.freedieting.com/tools/calorie_calculator.htm  and it tells me I need to consume around 1984 calories a day to lose weight and 2156 to maintain my current weight. 

So what gives?