Hitting Fat is caused by incorrect posture effecting spine angle and creating poor swing mechanics. Some of the common problems are listed below are:

Your centre of gravity is on your front foot so you can't move through the shot with your hips and legs. This means your balance will be poor with your head too far forward. With the centre of gravity, weight will be too far forward in your stance, your legs will move before you complete your back swing, consequently power supplied by your arms and shoulders only.

If the centre of balance is wrong due to disturbed posture, as indicated in the diagram (above left) by the yellow line, your head will move too far down on the right away from the target during the downswing or the back-swing resulting in a distorted swing plane. You will drop your left shoulder causing you to chop down on the ball, thus causing you to hit fat.

Poor biomechanics will also cause you to sway your body back during your back swing and then not coming forward to your original position during your back swing, will result in your shot hit fat or you will top the ball through poor distribution of weight as you swing through the ball. With poor posture causing the wrong centre of gravity the body will sway causing lack of balance and this will lead to backward movement on the back-swing and forward movement on the follow through. The hips will not rotate but will slide.

The diagram, (above right), shows the typical hitting fat posture with the centre of balance indicated by the red line. The faded image of a golfer dressed in blue is the correct posture. The correct posture should have a spine angle of 30 degrees, or as demonstrated in the diagram, at 11 o'clock or 1 o'clock depending if you are right or left handed.