I wouldn't be riding a bike 3 weeks out? I believe you will be using stomach muscles when you peddle. To me it doesn't seem worth it to me.
What do you mean normal diet? I think you should be eating puddings, jellos, fish, white rice, bannanas, applesauce, oatmeal and ... all soft foods. If your adding meats and breads and your 3 weeks out I thinik its too soon.