Dr. said that dreaded work - DIET

Ok. So I went to the dr. the other day. She said that I NEEDED to lose weight. This is something that I've been struggling with for some time now. I'm having a hard time losing, but now it's more of a "have to" more than a "want to" which makes it that much worse. And to top it off, they just told me that my heel pain was due to a heel spur and that I need to stay off my foot. So how will this work? How can I exercise if I can't use my foot?

So begins a new journey of my life. This will be quite difficult, but I'm told NOT impossible. Please leave me suggestions on how to accomplish this. I have more than 100 lbs to lose. I'm thinking about water aerobics but still researching that possibility. Any thoughts or suggestions?