Besides the health issues, getting your weight down will make your surgeries easier for the surgeons.
You wouldn't be the first one to use food as a comfort when things weren't going right.
Besides a diet, check with your Dr. as to what sort of exercise program you can do. Just walking a mile or two a day will start you burning more calories. When you exercise, your body burns more calories not only while you are exercising, but afterwards as well.
i wish you luck. You have a specific goal as to why you want to lose the weight, and that gives you something to work towards.
sam1234