There are 3500 calories in a pound of fat. There are 600 calories in a pound of muscle. An extra 500 calories a day will add a pound of fat a week to your body. There are individual tendencies to store fat cells in different areas of your body. This is an inherited characteristic that cannot be altered.
Women accumulate fat mostly in the legs, arms, and hips.
Men will gather fat in the back, and abdominal area. There is no such thing as spot removal of fat unless it is done surgically. When reducing, fat is mobilized out of the fat cells all over your body, then carried by the blood stream to your active cells, and burned for energy. This means that your fat deposits itself into specific areas of your body when you accumulate the fat, but reduces from all areas of your body when you lose it. The areas with the largest deposits are the last to show the benefits of a fat loss program.