I note that your main problem is overweight. You have already had two operations for umbilical hernia repair, and are now due for the third surgery. I also note that you have gained 40 lbs in the recent past. It is most important for you that you control your weight in order to have a successful outcome of the surgery. Your surgeon is the best judge to guide you regarding the technical aspects of the surgery. However, if you continue to gain weight, then the problem of recurrence will be of concern. You should also have complete health check up including thyroid check up. Take the help of a diet consultant as well regarding losing weight.