I can relate only too well.
For years the physician I go to has harassed me to lose weight. I kept telling him I've been obese all my life and I feel fine. He told me it at the time I was able to manage it, but the time would come when my skeleton would be unable to support the weight.
About eight months ago it hit. Pain in my ankles, knees and lower back. It was then that I thought maybe that old quack knows what he's talking about and I began to seriously diet.
It has gone pretty well. After the first five pounds the discomfort in my ankles went away, and after about twelve pounds the knees and back found relief (the back relief may have been assisted by the new mattress).
I'm now thirty pounds underway, but it's a bumpy road, for, as you mentioned, having used food for comfort and pleasure for all of one's life is a powerful pull.
"Keep your hand on the plow."