I had my surgery on November 3rd. For 10 days PRE op I was on a liquid diet of only Jello, yogurt, cottage cheese and Protein shakes. For ten days POST op I was on the diet also but without yogurt or Protein Shakes. Then ten days after they let me move to soft foods.
You will be alright, the reason you have to do it is because your muscles in your stomach contract when moving food so if you eat food that your stomach needs to move through ie, not soft foods or liquids, your band could slip. It's giving your stomach time to heal around the band without causing any chance of slippage.