Miasg's Journal, 28 January 2012

they say 3500 calories in one pound of fat and to loose one pound you have to have burn 3500 calories, or eat 3500 calories less than what you need to maintain your weight.  

It's 3500 calories but much more is factored in to weight loss. Your age, sex, genetics, activity levels, kinds of foods your eating , etc. Your body is made up of 60% water, so you see a lot of fluctuation on an hourly bases. If you eat high sodium foods, your body can retain a lot of water. When you go on a diet, you usually lose big at first because most of it is water weight. If you eat certain foods like high protein and high fiber foods, you can lose more quicker than when you eat a lot of high carbohydrate foods. But in the end, its mostly about burning off more than you take in. It takes a lot of work to lose fat and tone up. 

Thanks guys, this info is helpful. 3500 is a lot both ways.