I am extremely obese. Can anything be done to lift my stomach? It interferes with walking, sitting and lots of other things.

Dear softandfuffly,the optimal weight to have Tummy Tuck surgery is a very common question and for good reason. Having surgery before you reach your target weight can lead to suboptimal results if you were to lose more weight after surgery.
Good first questions to ask yourself are:
1. Am I at my goal weight?
2. Is my weight stable? have you lost or gained more than 10lbs in the past month? What was your weight last year?
3.  Are you eating a healthy diet and exercising?
If you are not at your goal weight or your weight is not stable, you should hold off on surgery.
Daniel Barrett, MD, MHA, MS 
Certified, American Board of Plastic Surgery 
Member, Am. Society of Plastic Surgery

You are asking an excellent question that online consultants will not be able to respond to with enough specificity to be truly helpful. I would suggest that you start with your primary care doctor and discuss your concerns. Referral to a weight loss specialist (for example a medically supervised well-organized weight-loss program)  may be a good place to start.  As you know, working with nutritionists and personal trainers may be very helpful.  Having said that, there are a subset of patients who  are above the ideal long-term stable weight who benefit from panniculectomy surgery. The panniculectomy operation involves excision of the lower abdominal wall pannus or overhanging skin/adipose tissue. It is not considered an  aesthetically driven procedure;  it is often performed to help with concerns such as skin breakdown, infections/rashes…   When you  achieve your long-term stable weight, through (probably) careful attention to diet and exercise, it will be time to consider  specific procedures to achieve aesthetic outcomes that you will be pleased with.  At that point, it will be important that you select your plastic surgeon carefully. Make sure that he/she is a board-certified plastic surgeon who can demonstrate lots of experience achieving the types of outcomes you will be pleased with. Then, careful communication of your goals will be important as well.
  Best wishes as you work towards your goals and for a final outcome that you will be very pleased with.